diff --git a/electron/main/ipc.ts b/electron/main/ipc.ts
index 3b5808e..c9a793e 100644
--- a/electron/main/ipc.ts
+++ b/electron/main/ipc.ts
@@ -354,71 +354,44 @@ async function callAiApi(imageBase64: string, rubric: string, config: { apiKey:
   deductions: string[]
   comment: string
 }> {
-  const systemRole = `你是高校阅卷专家，严格按照评分标准逐项评分。你必须只输出JSON，严禁包含\`\`\`markdown代码块、\`\`\`json标记、注释、说明文字或任何其他非JSON内容。输出必须以{开头，以}结尾，且必须是合法的JSON。`
+  const systemRole = `你是一名高校阅卷老师，根据评分标准和答案对学生答案评分。请输出JSON格式的结果。`
 
   const hasRefImage = !!extras?.referenceAnswerImage
 
   const prompt = hasRefImage
-    ? `${extras?.questionTitle ? `【题目】\n${extras.questionTitle}\n` : ''}【评分标准】
-${rubric || '无'}
+    ? `题目：${extras?.questionTitle || ''}
+评分标准：${rubric || '无'}
+参考答案：${extras?.referenceAnswer || '无'}
+满分：${extras?.maxScore ?? 100}
 
-【参考答案】
-${extras?.referenceAnswer || '无'}
+图片1是标准答案，图片2是学生答案。
+请根据评分标准和标准答案（图片1）给学生答案（图片2）评分。
 
-【满分】
-${extras?.maxScore ?? 100}
+评分规则：
+1. 逐项评分，各项得分之和不超过满分${extras?.maxScore ?? 100}
+2. 空白或无关答案给0分
+3. 部分正确酌情给分
 
-图片1：标准答案
-图片2：学生答案
+请输出JSON：
+{"score":分数,"confidence":置信度0~1,"deductions":["扣分项"],"comment":"评语"}
 
-请根据评分标准和标准答案（图片1）对学生答案（图片2）评分。
+只输出JSON，不要包含其他文字和markdown标记。`
+    : `题目：${extras?.questionTitle || ''}
+评分标准：${rubric || '无'}
+参考答案：${extras?.referenceAnswer || '无'}
+满分：${extras?.maxScore ?? 100}
 
----
+图片是学生答案，请根据评分标准评分。
 
-【评分规则】
-1. 根据评分标准中的各项指标逐项评分，每项给出得分和说明
-2. 各评分项得分之和不得超过满分${extras?.maxScore ?? 100}分
-3. 如果学生答案为空、空白或明显与题目无关，直接给0分
-4. 部分正确时按评分标准酌情给分
+评分规则：
+1. 逐项评分，各项得分之和不超过满分${extras?.maxScore ?? 100}
+2. 空白或无关答案给0分
+3. 部分正确酌情给分
 
-【输出要求】
-你必须严格输出以下格式的纯JSON，严禁包含\`\`\`、\`\`\`json、markdown代码块、注释或任何说明文字。整个回复必须是合法的JSON对象，以{开始，以}结束：
-{
-  "score": <总分>,
-  "confidence": <置信度0~1>,
-  "deductions": ["扣分项说明1", "扣分项说明2"],
-  "comment": "总评语及逐项得分说明"
-}
-再次强调：只输出JSON，禁止任何其他内容。`
-    : `${extras?.questionTitle ? `【题目】\n${extras.questionTitle}\n` : ''}【评分标准】
-${rubric || '无'}
+请输出JSON：
+{"score":分数,"confidence":置信度0~1,"deductions":["扣分项"],"comment":"评语"}
 
-【参考答案】
-${extras?.referenceAnswer || '无'}
-
-【满分】
-${extras?.maxScore ?? 100}
-
-图片：学生答案
-请根据评分标准对学生答案评分。
-
----
-
-【评分规则】
-1. 根据评分标准中的各项指标逐项评分，每项给出得分和说明
-2. 各评分项得分之和不得超过满分${extras?.maxScore ?? 100}分
-3. 如果学生答案为空、空白或明显与题目无关，直接给0分
-4. 部分正确时按评分标准酌情给分
-
-【输出要求】
-你必须严格输出以下格式的纯JSON，严禁包含\`\`\`、\`\`\`json、markdown代码块、注释或任何说明文字。整个回复必须是合法的JSON对象，以{开始，以}结束：
-{
-  "score": <总分>,
-  "confidence": <置信度0~1>,
-  "deductions": ["扣分项说明1", "扣分项说明2"],
-  "comment": "总评语及逐项得分说明"
-}
-再次强调：只输出JSON，禁止任何其他内容。`
+只输出JSON，不要包含其他文字和markdown标记。`
 
   const axios = require('axios')
 
diff --git a/src/components/FloatingToolbar.vue b/src/components/FloatingToolbar.vue
index d8c36c3..3245411 100644
--- a/src/components/FloatingToolbar.vue
+++ b/src/components/FloatingToolbar.vue
@@ -30,6 +30,10 @@
           <span class="btn-icon">📜</span>
           <span class="btn-label">历史</span>
         </el-button>
+        <el-button class="toolbar-btn collapse-btn" @click="showMenu = false">
+          <span class="btn-icon">↩</span>
+          <span class="btn-label">收起</span>
+        </el-button>
       </template>
 
       <el-button class="toolbar-btn" @click="openSettings">
@@ -46,6 +50,7 @@ import { ElMessage } from 'element-plus'
 import { useAppStore } from '@/stores/app'
 import { useGradingStore } from '@/stores/grading'
 import { useSettingsStore } from '@/stores/settings'
+import { addWatermark } from '@/utils/image'
 
 const appStore = useAppStore()
 const gradingStore = useGradingStore()
@@ -69,9 +74,9 @@ let cleanupScreenshotListener: (() => void) | null = null
 onMounted(() => {
   resizeWindow()
   if (window.electronAPI) {
-    cleanupScreenshotListener = window.electronAPI.screenshot.onCompleted((base64: string) => {
+    cleanupScreenshotListener = window.electronAPI.screenshot.onCompleted(async (base64: string) => {
       if (!appStore.isGrading) {
-        gradingStore.setImage(base64)
+        gradingStore.setImage(await addWatermark(base64, '学生答案'))
         startGrading()
       }
     })
@@ -90,7 +95,7 @@ async function selectImage() {
   if (!window.electronAPI) return
   const data = await window.electronAPI.dialog.openImage()
   if (data) {
-    gradingStore.setImage(data.base64)
+    gradingStore.setImage(await addWatermark(data.base64, '学生答案'))
     startGrading()
   }
 }
@@ -206,6 +211,13 @@ function openSettings() { window.electronAPI?.dialog.open('settings') }
 .sub-btn {
   padding: 4px 8px !important;
 }
+.collapse-btn {
+  padding: 4px 6px !important;
+  color: rgba(255, 255, 255, 0.5) !important;
+}
+.collapse-btn:hover {
+  color: rgba(255, 255, 255, 0.9) !important;
+}
 
 .toolbar-btn {
   -webkit-app-region: no-drag;
diff --git a/src/components/ResultDrawer.vue b/src/components/ResultDrawer.vue
index 282212b..fc2ae8c 100644
--- a/src/components/ResultDrawer.vue
+++ b/src/components/ResultDrawer.vue
@@ -25,9 +25,15 @@
           <div class="section-title">当前评分标准</div>
           <div class="rubric-text">{{ currentQuestion.rubric }}</div>
         </div>
-        <div class="result-section" v-if="currentQuestion.referenceAnswer">
+
+        <div class="result-section" v-if="gradingStore.currentImage">
+          <div class="section-title">学生答案图片</div>
+          <img class="student-image" :src="'data:image/png;base64,' + gradingStore.currentImage" />
+        </div>
+
+        <div class="result-section" v-if="currentQuestion.referenceAnswer || currentQuestion.referenceAnswerImage">
           <div class="section-title">参考答案</div>
-          <div class="reference-text">{{ currentQuestion.referenceAnswer }}</div>
+          <div class="reference-text" v-if="currentQuestion.referenceAnswer">{{ currentQuestion.referenceAnswer }}</div>
           <img v-if="currentQuestion.referenceAnswerImage" class="ref-image" :src="currentQuestion.referenceAnswerImage" />
         </div>
 
@@ -355,7 +361,7 @@ async function confirmScore() {
   border-radius: 6px;
   white-space: pre-wrap;
 }
-.ref-image {
+.ref-image, .student-image {
   max-width: 100%;
   max-height: 300px;
   border-radius: 6px;
diff --git a/src/components/RubricEditor.vue b/src/components/RubricEditor.vue
index d8ff8fc..173da9a 100644
--- a/src/components/RubricEditor.vue
+++ b/src/components/RubricEditor.vue
@@ -28,7 +28,7 @@
             <div class="ref-image-section">
               <template v-if="questions[activeIndex].referenceAnswerImage">
                 <div class="ref-image-preview">
-                  <img :src="'data:image/png;base64,' + questions[activeIndex].referenceAnswerImage" />
+                  <img :src="questions[activeIndex].referenceAnswerImage" />
                   <el-button size="small" type="danger" text @click="removeRefImage(activeIndex)">删除图片</el-button>
                 </div>
               </template>
@@ -61,6 +61,7 @@ import { ElMessage } from 'element-plus'
 import { useAppStore } from '@/stores/app'
 import { useGradingStore } from '@/stores/grading'
 import type { QuestionItem } from '@/types'
+import { addWatermark } from '@/utils/image'
 
 const appStore = useAppStore()
 const gradingStore = useGradingStore()
@@ -142,7 +143,7 @@ async function uploadRefImage(idx: number) {
   if (!window.electronAPI) return
   const data = await window.electronAPI.dialog.openImage()
   if (data) {
-    questions.value[idx].referenceAnswerImage = `data:${data.mime};base64,${data.base64}`
+    questions.value[idx].referenceAnswerImage = `data:image/${data.mime};base64,${await addWatermark(data.base64, '参考答案')}`
   }
 }
 
diff --git a/src/utils/image.ts b/src/utils/image.ts
new file mode 100644
index 0000000..1f489d4
--- /dev/null
+++ b/src/utils/image.ts
@@ -0,0 +1,21 @@
+export function addWatermark(base64: string, text: string): Promise<string> {
+  return new Promise((resolve, reject) => {
+    const img = new Image()
+    img.onload = () => {
+      const canvas = document.createElement('canvas')
+      canvas.width = img.width
+      canvas.height = img.height
+      const ctx = canvas.getContext('2d')
+      if (!ctx) return reject(new Error('Canvas 2D context not available'))
+      ctx.drawImage(img, 0, 0)
+      ctx.font = `bold ${Math.max(28, Math.round(img.width / 20))}px sans-serif`
+      ctx.fillStyle = 'rgba(255, 0, 0, 0.85)'
+      ctx.textBaseline = 'top'
+      const padding = Math.max(8, Math.round(img.width / 60))
+      ctx.fillText(text, padding, padding)
+      resolve(canvas.toDataURL('image/png').replace(/^data:image\/png;base64,/, ''))
+    }
+    img.onerror = () => reject(new Error('Failed to load image for watermark'))
+    img.src = `data:image/png;base64,${base64}`
+  })
+}