diff --git a/runtime/Sim.WinForms/Resources/README.md b/runtime/Sim.WinForms/Resources/README.md
index 501d895..19be07f 100644
--- a/runtime/Sim.WinForms/Resources/README.md
+++ b/runtime/Sim.WinForms/Resources/README.md
@@ -2,6 +2,6 @@
 
 学生在"项目资源"里添加的图片和声音（`Properties.Resources.xxx`），名字和尺寸与教材一致，全部由平台自绘或合成（不使用教材配套资料里的素材）。
 
-- `gallery/`：发布给运行器和网页的文件，`index.json` 是清单（名字、文件、中文说明、类型）。
+- `gallery/`：发布给运行器和网页的文件，`index.json` 是清单（名字、文件、中文说明、类型；图片还有编号 key 和两倍图 hidpi，由 `build-gallery.sh` 写入）。`name.png` 是原尺寸，学生程序读到的就是它；`name.2x.png` 只给高分辨率屏幕的浏览器显示用，宽高仍按原尺寸。
 - `svg/`：图片的源文件；`project8.py` 生成项目 8 的那些 SVG。改了以后运行 `python3 project8.py && sh build-gallery.sh` 重新生成 PNG（需要 rsvg-convert 和思源黑体）。
 - `gallery/ring.mp3`：用 ffmpeg 合成的门铃声（叮—咚），命令见提交记录。
diff --git a/runtime/Sim.WinForms/Resources/build-gallery.sh b/runtime/Sim.WinForms/Resources/build-gallery.sh
index 32adb61..e218232 100644
--- a/runtime/Sim.WinForms/Resources/build-gallery.sh
+++ b/runtime/Sim.WinForms/Resources/build-gallery.sh
@@ -1,6 +1,23 @@
 #!/bin/sh
-# 把 svg/ 下的素材渲染成 gallery/ 下的 PNG（尺寸取 SVG 自己的 width / height）。需要 rsvg-convert 和思源黑体等中文字体。
+# 把 svg/ 下的素材渲染成 gallery/ 下的 PNG：name.png 是原尺寸（学生程序读到的图片，宽高和教材一致），
+# name.2x.png 是两倍尺寸（只给高分辨率屏幕的浏览器显示用）。然后把每张图的编号（原尺寸 PNG 的 SHA-1，
+# 和运行器给图片的编号相同）和两倍图的文件名写进 gallery/index.json。需要 rsvg-convert 和思源黑体等中文字体。
 cd "$(dirname "$0")"
 for f in svg/*.svg; do
-  rsvg-convert "$f" -o "gallery/$(basename "$f" .svg).png"
+  name=$(basename "$f" .svg)
+  rsvg-convert "$f" -o "gallery/$name.png"
+  rsvg-convert -z 2 "$f" -o "gallery/$name.2x.png"
 done
+python3 - <<'PY'
+import hashlib, json, os
+items = json.load(open("gallery/index.json", encoding="utf-8"))
+for item in items:
+    if item["kind"] != "image":
+        continue
+    item["key"] = hashlib.sha1(open(f"gallery/{item['file']}", "rb").read()).hexdigest()
+    hidpi = item["file"].replace(".png", ".2x.png")
+    if os.path.exists(f"gallery/{hidpi}"):
+        item["hidpi"] = hidpi
+lines = ",\n".join("  " + json.dumps(i, ensure_ascii=False) for i in items)
+open("gallery/index.json", "w", encoding="utf-8").write(f"[\n{lines}\n]\n")
+PY
diff --git a/runtime/Sim.WinForms/Resources/gallery/arrow_left_normal.2x.png b/runtime/Sim.WinForms/Resources/gallery/arrow_left_normal.2x.png
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diff --git a/runtime/Sim.WinForms/Resources/gallery/bg_from1.2x.png b/runtime/Sim.WinForms/Resources/gallery/bg_from1.2x.png
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index 0000000..f6ece1d
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diff --git a/runtime/Sim.WinForms/Resources/gallery/bg_home.2x.png b/runtime/Sim.WinForms/Resources/gallery/bg_home.2x.png
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diff --git a/runtime/Sim.WinForms/Resources/gallery/btn_arrow_down_press.2x.png b/runtime/Sim.WinForms/Resources/gallery/btn_arrow_down_press.2x.png
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index 0000000..9de4c3b
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diff --git a/runtime/Sim.WinForms/Resources/gallery/btn_arrow_left_normal.2x.png b/runtime/Sim.WinForms/Resources/gallery/btn_arrow_left_normal.2x.png
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index 0000000..1a3b91b
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diff --git a/runtime/Sim.WinForms/Resources/gallery/btn_arrow_left_press.2x.png b/runtime/Sim.WinForms/Resources/gallery/btn_arrow_left_press.2x.png
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diff --git a/runtime/Sim.WinForms/Resources/gallery/btn_arrow_right_normal.2x.png b/runtime/Sim.WinForms/Resources/gallery/btn_arrow_right_normal.2x.png
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diff --git a/runtime/Sim.WinForms/Resources/gallery/btn_arrow_right_press.2x.png b/runtime/Sim.WinForms/Resources/gallery/btn_arrow_right_press.2x.png
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index 0000000..4e00a8f
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diff --git a/runtime/Sim.WinForms/Resources/gallery/btn_arrow_up_normal.2x.png b/runtime/Sim.WinForms/Resources/gallery/btn_arrow_up_normal.2x.png
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diff --git a/runtime/Sim.WinForms/Resources/gallery/btn_arrow_up_press.2x.png b/runtime/Sim.WinForms/Resources/gallery/btn_arrow_up_press.2x.png
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index 0000000..0c63238
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diff --git a/runtime/Sim.WinForms/Resources/gallery/day_01.2x.png b/runtime/Sim.WinForms/Resources/gallery/day_01.2x.png
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index 0000000..fb2bf3e
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diff --git a/runtime/Sim.WinForms/Resources/gallery/day_02.2x.png b/runtime/Sim.WinForms/Resources/gallery/day_02.2x.png
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index 0000000..55f0225
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diff --git a/runtime/Sim.WinForms/Resources/gallery/ico_title.2x.png b/runtime/Sim.WinForms/Resources/gallery/ico_title.2x.png
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index 0000000..887ff05
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diff --git a/runtime/Sim.WinForms/Resources/gallery/icon_02.2x.png b/runtime/Sim.WinForms/Resources/gallery/icon_02.2x.png
new file mode 100644
index 0000000..25e32e4
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diff --git a/runtime/Sim.WinForms/Resources/gallery/icon_03.2x.png b/runtime/Sim.WinForms/Resources/gallery/icon_03.2x.png
new file mode 100644
index 0000000..3752de7
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diff --git a/runtime/Sim.WinForms/Resources/gallery/icon_04.2x.png b/runtime/Sim.WinForms/Resources/gallery/icon_04.2x.png
new file mode 100644
index 0000000..dc44c5e
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diff --git a/runtime/Sim.WinForms/Resources/gallery/icon_monitor.2x.png b/runtime/Sim.WinForms/Resources/gallery/icon_monitor.2x.png
new file mode 100644
index 0000000..fc15ab1
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diff --git a/runtime/Sim.WinForms/Resources/gallery/index.json b/runtime/Sim.WinForms/Resources/gallery/index.json
index 3f1d233..e4b331e 100644
--- a/runtime/Sim.WinForms/Resources/gallery/index.json
+++ b/runtime/Sim.WinForms/Resources/gallery/index.json
@@ -1,27 +1,27 @@
 [
-  { "name": "switch_on", "file": "switch_on.png", "label": "开关：开", "kind": "image" },
-  { "name": "switch_off", "file": "switch_off.png", "label": "开关：关", "kind": "image" },
-  { "name": "ring", "file": "ring.mp3", "label": "铃声", "kind": "audio" },
-  { "name": "ico_title", "file": "ico_title.png", "label": "标题：智慧校园", "kind": "image" },
-  { "name": "bg_home", "file": "bg_home.png", "label": "主界面背景：校园", "kind": "image" },
-  { "name": "icon_02", "file": "icon_02.png", "label": "图标：校园环境", "kind": "image" },
-  { "name": "icon_03", "file": "icon_03.png", "label": "图标：校园安防", "kind": "image" },
-  { "name": "icon_04", "file": "icon_04.png", "label": "图标：退出", "kind": "image" },
-  { "name": "day_01", "file": "day_01.png", "label": "路灯场景：亮灯", "kind": "image" },
-  { "name": "day_02", "file": "day_02.png", "label": "路灯场景：灭灯", "kind": "image" },
-  { "name": "bg_from1", "file": "bg_from1.png", "label": "面板背景（宽）", "kind": "image" },
-  { "name": "bg_from2", "file": "bg_from2.png", "label": "面板背景（窄）", "kind": "image" },
-  { "name": "icon_monitor", "file": "icon_monitor.png", "label": "监控：无画面", "kind": "image" },
-  { "name": "panel_video_ctrl", "file": "panel_video_ctrl.png", "label": "监控：方向盘底座", "kind": "image" },
-  { "name": "btn_arrow_up_normal", "file": "btn_arrow_up_normal.png", "label": "方向键：上", "kind": "image" },
-  { "name": "btn_arrow_up_press", "file": "btn_arrow_up_press.png", "label": "方向键：上（按下）", "kind": "image" },
-  { "name": "btn_arrow_down_normal", "file": "btn_arrow_down_normal.png", "label": "方向键：下", "kind": "image" },
-  { "name": "btn_arrow_down_press", "file": "btn_arrow_down_press.png", "label": "方向键：下（按下）", "kind": "image" },
-  { "name": "btn_arrow_left_normal", "file": "btn_arrow_left_normal.png", "label": "方向键：左", "kind": "image" },
-  { "name": "btn_arrow_left_press", "file": "btn_arrow_left_press.png", "label": "方向键：左（按下）", "kind": "image" },
-  { "name": "btn_arrow_right_normal", "file": "btn_arrow_right_normal.png", "label": "方向键：右", "kind": "image" },
-  { "name": "btn_arrow_right_press", "file": "btn_arrow_right_press.png", "label": "方向键：右（按下）", "kind": "image" },
-  { "name": "arrow_left_normal", "file": "arrow_left_normal.png", "label": "翻页：上一张", "kind": "image" },
-  { "name": "arrow_right_normal", "file": "arrow_right_normal.png", "label": "翻页：下一张", "kind": "image" },
-  { "name": "windowstate_closed_hover", "file": "windowstate_closed_hover.png", "label": "关闭按钮", "kind": "image" }
+  {"name": "switch_on", "file": "switch_on.png", "label": "开关：开", "kind": "image", "key": "6e660e1ff6fc2ff3167919bc386c300112bbce72", "hidpi": "switch_on.2x.png"},
+  {"name": "switch_off", "file": "switch_off.png", "label": "开关：关", "kind": "image", "key": "5d748b614084e878d6189d22f27813477cb8f4d9", "hidpi": "switch_off.2x.png"},
+  {"name": "ring", "file": "ring.mp3", "label": "铃声", "kind": "audio"},
+  {"name": "ico_title", "file": "ico_title.png", "label": "标题：智慧校园", "kind": "image", "key": "8a4db5ad7bc26136ae48056d6e71fa077e36e80f", "hidpi": "ico_title.2x.png"},
+  {"name": "bg_home", "file": "bg_home.png", "label": "主界面背景：校园", "kind": "image", "key": "e56bcc13f7128dec305b6012b255d63fb0f94450", "hidpi": "bg_home.2x.png"},
+  {"name": "icon_02", "file": "icon_02.png", "label": "图标：校园环境", "kind": "image", "key": "fa6a1eaa87c87913803c77f928fa9c16b7f4bf6d", "hidpi": "icon_02.2x.png"},
+  {"name": "icon_03", "file": "icon_03.png", "label": "图标：校园安防", "kind": "image", "key": "d085064a505544968278a85233b7d9ac23661169", "hidpi": "icon_03.2x.png"},
+  {"name": "icon_04", "file": "icon_04.png", "label": "图标：退出", "kind": "image", "key": "c853d74ecab64a9ee85bdf24ccfa63e80123cce3", "hidpi": "icon_04.2x.png"},
+  {"name": "day_01", "file": "day_01.png", "label": "路灯场景：亮灯", "kind": "image", "key": "05065abdb4538906bd7c86e940ab5fb02d51469d", "hidpi": "day_01.2x.png"},
+  {"name": "day_02", "file": "day_02.png", "label": "路灯场景：灭灯", "kind": "image", "key": "470d523e90e188fe5c423d8cffeae6993d5528ff", "hidpi": "day_02.2x.png"},
+  {"name": "bg_from1", "file": "bg_from1.png", "label": "面板背景（宽）", "kind": "image", "key": "7a8c0a16fcab37b28a66e041024b25341cc69462", "hidpi": "bg_from1.2x.png"},
+  {"name": "bg_from2", "file": "bg_from2.png", "label": "面板背景（窄）", "kind": "image", "key": "52497df301d2b7e4eac0c297ce2316ef24863c47", "hidpi": "bg_from2.2x.png"},
+  {"name": "icon_monitor", "file": "icon_monitor.png", "label": "监控：无画面", "kind": "image", "key": "23e6f1efc0f382c17d8a091b76531a3b5879349d", "hidpi": "icon_monitor.2x.png"},
+  {"name": "panel_video_ctrl", "file": "panel_video_ctrl.png", "label": "监控：方向盘底座", "kind": "image", "key": "396443a1d8c141942c0f447e0c69786cf6ad3350", "hidpi": "panel_video_ctrl.2x.png"},
+  {"name": "btn_arrow_up_normal", "file": "btn_arrow_up_normal.png", "label": "方向键：上", "kind": "image", "key": "3c8b75ad465c8a61d0279facc233a0c64b62205a", "hidpi": "btn_arrow_up_normal.2x.png"},
+  {"name": "btn_arrow_up_press", "file": "btn_arrow_up_press.png", "label": "方向键：上（按下）", "kind": "image", "key": "51e1b9926d2bd611e3fda74a01231b46a930c460", "hidpi": "btn_arrow_up_press.2x.png"},
+  {"name": "btn_arrow_down_normal", "file": "btn_arrow_down_normal.png", "label": "方向键：下", "kind": "image", "key": "caf46f81c15aaca788462ebc47e58df299f097d9", "hidpi": "btn_arrow_down_normal.2x.png"},
+  {"name": "btn_arrow_down_press", "file": "btn_arrow_down_press.png", "label": "方向键：下（按下）", "kind": "image", "key": "88c1bea8d6fad99b14658d8265a88b04bc595006", "hidpi": "btn_arrow_down_press.2x.png"},
+  {"name": "btn_arrow_left_normal", "file": "btn_arrow_left_normal.png", "label": "方向键：左", "kind": "image", "key": "a38beb2373154d0474ad1715035aec5e2adf8c3f", "hidpi": "btn_arrow_left_normal.2x.png"},
+  {"name": "btn_arrow_left_press", "file": "btn_arrow_left_press.png", "label": "方向键：左（按下）", "kind": "image", "key": "47bd7a8ffc077130a8ceca627383a4647729c638", "hidpi": "btn_arrow_left_press.2x.png"},
+  {"name": "btn_arrow_right_normal", "file": "btn_arrow_right_normal.png", "label": "方向键：右", "kind": "image", "key": "e69e459f54d67e2c52128015bd6cfcf0e800a893", "hidpi": "btn_arrow_right_normal.2x.png"},
+  {"name": "btn_arrow_right_press", "file": "btn_arrow_right_press.png", "label": "方向键：右（按下）", "kind": "image", "key": "afb1f5fe5a14b7cef298a7d4c67c4cece9e01170", "hidpi": "btn_arrow_right_press.2x.png"},
+  {"name": "arrow_left_normal", "file": "arrow_left_normal.png", "label": "翻页：上一张", "kind": "image", "key": "5a9036955f791f0c41ba52afffb5ecc640d137f1", "hidpi": "arrow_left_normal.2x.png"},
+  {"name": "arrow_right_normal", "file": "arrow_right_normal.png", "label": "翻页：下一张", "kind": "image", "key": "62c53dfb3acf291ef07d6e52fcb989cd48c020b9", "hidpi": "arrow_right_normal.2x.png"},
+  {"name": "windowstate_closed_hover", "file": "windowstate_closed_hover.png", "label": "关闭按钮", "kind": "image", "key": "e361965dbd881dc21511208ce11f649517e8ddb6", "hidpi": "windowstate_closed_hover.2x.png"}
 ]
diff --git a/runtime/Sim.WinForms/Resources/gallery/panel_video_ctrl.2x.png b/runtime/Sim.WinForms/Resources/gallery/panel_video_ctrl.2x.png
new file mode 100644
index 0000000..db41bbb
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diff --git a/runtime/Sim.WinForms/Resources/gallery/switch_off.2x.png b/runtime/Sim.WinForms/Resources/gallery/switch_off.2x.png
new file mode 100644
index 0000000..cf30e1b
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diff --git a/runtime/Sim.WinForms/Resources/gallery/switch_on.2x.png b/runtime/Sim.WinForms/Resources/gallery/switch_on.2x.png
new file mode 100644
index 0000000..d1e486c
Binary files /dev/null and b/runtime/Sim.WinForms/Resources/gallery/switch_on.2x.png differ
diff --git a/runtime/Sim.WinForms/Resources/gallery/windowstate_closed_hover.2x.png b/runtime/Sim.WinForms/Resources/gallery/windowstate_closed_hover.2x.png
new file mode 100644
index 0000000..eaaebf8
Binary files /dev/null and b/runtime/Sim.WinForms/Resources/gallery/windowstate_closed_hover.2x.png differ
diff --git a/server/src/app.ts b/server/src/app.ts
index 850bca1..f96d067 100644
--- a/server/src/app.ts
+++ b/server/src/app.ts
@@ -80,7 +80,8 @@ export function createApp(db: Database, gradingQueue: GradingQueue, aiQueue: AiQ
     if (!/^[\w.-]+$/.test(name)) return c.notFound()
     const file = Bun.file(`${dirname(config.runnerDll)}/Resources/gallery/${name}`)
     if (!(await file.exists())) return c.notFound()
-    return new Response(file, { headers: { 'Cache-Control': 'public, max-age=3600' } })
+    // 清单随部署更新（新素材、图片编号），每次都向服务器确认；图片缓存一小时
+    return new Response(file, { headers: { 'Cache-Control': name === 'index.json' ? 'no-cache' : 'public, max-age=3600' } })
   })
 
   // 其余接口都要先登录（请求头 Authorization: Bearer <令牌>）
diff --git a/web/src/designer/ResourcesDialog.vue b/web/src/designer/ResourcesDialog.vue
index 119ec14..d3f1d04 100644
--- a/web/src/designer/ResourcesDialog.vue
+++ b/web/src/designer/ResourcesDialog.vue
@@ -45,13 +45,20 @@ function save() {
   <NModal :show="show" preset="card" title="项目资源" style="width: 560px; max-width: calc(100vw - 32px)" @update:show="emit('update:show', $event)">
     <p class="note">勾选要加入项目的图片和声音（平台素材库，名字和教材一致）。代码里写 <code>Properties.Resources.名字</code>，图片框的"图片"属性也可以直接选。</p>
     <div class="items">
-      <label v-for="item in gallery" :key="item.name" class="item" :class="{ on: chosen.has(item.name) }">
-        <NCheckbox :checked="chosen.has(item.name)" @update:checked="toggle(item.name, $event)" />
-        <img v-if="item.kind === 'image'" :src="`/resources/${item.file}`" alt="" class="thumb" />
-        <NButton v-else size="tiny" class="audio" @click.prevent="listen(item.file)">▶ 试听</NButton>
+      <!-- 点整行都能勾选；复选框和"试听"自己处理点击，不再传给这一行 -->
+      <div v-for="item in gallery" :key="item.name" class="item" :class="{ on: chosen.has(item.name) }" @click="toggle(item.name, !chosen.has(item.name))">
+        <NCheckbox :checked="chosen.has(item.name)" @click.stop @update:checked="toggle(item.name, $event)" />
+        <img
+          v-if="item.kind === 'image'"
+          :src="`/resources/${item.file}`"
+          :srcset="item.hidpi ? `/resources/${item.file} 1x, /resources/${item.hidpi} 2x` : undefined"
+          alt=""
+          class="thumb"
+        />
+        <NButton v-else size="tiny" class="audio" @click.stop="listen(item.file)">▶ 试听</NButton>
         <span class="name">{{ item.name }}</span>
         <span class="label">{{ item.label }}</span>
-      </label>
+      </div>
       <div v-if="gallery.length === 0" class="note">正在加载素材库…</div>
     </div>
     <template #footer>
@@ -106,6 +113,11 @@ function save() {
   max-height: 40px;
 }
 
+/* 灰色棋盘格底：透明背景上的白色图片（如 ico_title 的白字）也看得见 */
+.thumb {
+  background: repeating-conic-gradient(#9ca3af 0 25%, #c4c9d0 0 50%) 0 0 / 10px 10px;
+}
+
 .audio {
   justify-self: start;
 }
diff --git a/web/src/designer/resources.ts b/web/src/designer/resources.ts
index 7accc0e..59d6c5c 100644
--- a/web/src/designer/resources.ts
+++ b/web/src/designer/resources.ts
@@ -11,6 +11,10 @@ export interface GalleryItem {
   /** 中文说明 */
   label: string
   kind: 'image' | 'audio'
+  /** 图片的编号（原尺寸 PNG 的 SHA-1，和运行器给图片的编号相同） */
+  key?: string
+  /** 两倍尺寸的图片文件，高分辨率屏幕上显示用 */
+  hidpi?: string
 }
 
 export const RESOURCES_FILE = 'Properties/Resources.Designer.cs'
diff --git a/web/src/run/RunArea.vue b/web/src/run/RunArea.vue
index b9ab484..2d88676 100644
--- a/web/src/run/RunArea.vue
+++ b/web/src/run/RunArea.vue
@@ -2,6 +2,7 @@
 // 运行区：学生程序的窗体（在一块"桌面"上）、提示框、虚拟实训台，以及编译错误和控制台输出。
 // 实验页和老师的评阅页共用。
 import { computed, onBeforeUnmount, onMounted, provide, ref } from 'vue'
+import { loadGallery } from '../designer/resources'
 import TrainingBoard from '../scene/TrainingBoard.vue'
 import type { SizeValue } from '../winforms/format'
 import FormWindow, { WINDOW_MARGIN, WINDOW_STEP } from '../winforms/FormWindow.vue'
@@ -14,6 +15,8 @@ const emit = defineEmits<{ diagnostic: [file: string, line: number, column: numb
 
 const state = props.session.state
 provide(RUN_IMAGES, props.session.images)
+// 素材库清单：认出素材图片，在高分辨率屏幕上换成两倍图
+void loadGallery()
 
 /** 照片列表里点开看大图 */
 const viewing = ref<{ path: string; url: string } | null>(null)
diff --git a/web/src/winforms/ControlView.vue b/web/src/winforms/ControlView.vue
index 5a9f4e5..f17a4d5 100644
--- a/web/src/winforms/ControlView.vue
+++ b/web/src/winforms/ControlView.vue
@@ -4,7 +4,7 @@
 import { computed, inject, provide, ref, type CSSProperties } from 'vue'
 import type { ControlNode, UserAction } from '@iot/shared'
 import { AMBIENT_BACK_COLOR, AMBIENT_BACK_TYPES, boxCss, DEFAULT_BACK_COLOR, displayText } from './format'
-import { backgroundCss, RUN_IMAGES, type ImageValue } from './images'
+import { backgroundCss, imageSources, RUN_IMAGES, srcset, type ImageValue } from './images'
 import ChartControl from './ChartControl.vue'
 import DataGridViewControl from './DataGridViewControl.vue'
 import DateTimePickerControl from './DateTimePickerControl.vue'
@@ -72,7 +72,7 @@ function selectItem(index: number) {
 
 // PictureBox：按 SizeMode 摆放图片
 const image = computed(() => p.value.Image as ImageValue | null | undefined)
-const imageUrl = computed(() => (image.value ? image.value.url ?? runImages.get(image.value.key) : undefined))
+const imageSrc = computed(() => imageSources(image.value, runImages))
 // 设计器预览里不知道素材的尺寸，原样大小显示时让浏览器按图片本身的大小
 const naturalSize = computed(() => (image.value?.width ? { width: `${image.value.width}px`, height: `${image.value.height}px` } : {}))
 const imageStyle = computed((): CSSProperties => {
@@ -182,7 +182,7 @@ const itemHeight = computed(() => `${(p.value.ItemHeight as number | undefined)
     @pointerdown="mouse('mouseDown', $event)"
     @pointerup="mouse('mouseUp', $event)"
   >
-    <img v-if="imageUrl" :src="imageUrl" :style="imageStyle" alt="" draggable="false" />
+    <img v-if="imageSrc" :src="imageSrc.src" :srcset="srcset(imageSrc)" :style="imageStyle" alt="" draggable="false" />
     <ControlView v-for="child in childrenTopLast" :key="child.id" :node="child" :act="props.act" />
   </div>
 
diff --git a/web/src/winforms/images.ts b/web/src/winforms/images.ts
index 4e0d1d5..7967829 100644
--- a/web/src/winforms/images.ts
+++ b/web/src/winforms/images.ts
@@ -1,6 +1,7 @@
 // 运行时图片：运行器发来的图片数据由 RunSession 保存成 blob 网址，控件属性里只带图片编号。
 // 运行区 provide，ControlView inject；设计器预览没有运行时图片，取到空表。
 import type { CSSProperties, InjectionKey } from 'vue'
+import { gallery } from '../designer/resources'
 
 export const RUN_IMAGES: InjectionKey<ReadonlyMap<string, string>> = Symbol('runImages')
 
@@ -13,12 +14,31 @@ export interface ImageValue {
   url?: string
 }
 
+/**
+ * 图片的网址。素材库里的图片（按编号或素材网址认出来）另有两倍尺寸的版本，
+ * 高分辨率屏幕（系统缩放 150%、200%）上用它，不然浏览器放大原图会发虚；程序读到的宽高不变。
+ */
+export function imageSources(value: unknown, images: ReadonlyMap<string, string>): { src: string; hidpi?: string } | undefined {
+  const image = value as ImageValue | null | undefined
+  if (!image) return undefined
+  const item = gallery.value.find((g) => (image.key && g.key === image.key) || (image.url && image.url === `/resources/${g.file}`))
+  if (item?.hidpi) return { src: `/resources/${item.file}`, hidpi: `/resources/${item.hidpi}` }
+  const src = image.url ?? images.get(image.key)
+  return src ? { src } : undefined
+}
+
+/** <img> 的 srcset：有两倍图时浏览器按屏幕分辨率选 */
+export const srcset = (sources: { src: string; hidpi?: string } | undefined) =>
+  sources?.hidpi ? `${sources.src} 1x, ${sources.hidpi} 2x` : undefined
+
 /** 背景图片的 CSS：BackgroundImageLayout 为 Tile（默认，平铺）、None（左上角一张）、Center、Stretch、Zoom */
 export function backgroundCss(value: unknown, layout: unknown, images: ReadonlyMap<string, string>): CSSProperties {
-  const image = value as ImageValue | null | undefined
-  const url = image ? image.url ?? images.get(image.key) : undefined
-  if (!url) return {}
-  const base = { backgroundImage: `url("${url}")` }
+  const sources = imageSources(value, images)
+  if (!sources) return {}
+  // image-set 里的两倍图按 2x 显示，平铺、居中、左上角时仍是原尺寸
+  const base: CSSProperties = {
+    backgroundImage: sources.hidpi ? `image-set(url("${sources.src}") 1x, url("${sources.hidpi}") 2x)` : `url("${sources.src}")`,
+  }
   switch (layout) {
     case 'None':
       return { ...base, backgroundRepeat: 'no-repeat', backgroundPosition: '0 0' }