diff --git a/browser/components/MarkdownPreview.js b/browser/components/MarkdownPreview.js
index e93312ef..a6819ce9 100755
--- a/browser/components/MarkdownPreview.js
+++ b/browser/components/MarkdownPreview.js
@@ -833,81 +833,80 @@ export default class MarkdownPreview extends React.Component {
       }
     )
 
-    document.querySelectorAll('iframe').forEach(item => {
-      const rect = item.getBoundingClientRect()
-      const imgList = item.contentWindow.document.body.querySelectorAll('img')
-      for (const img of imgList) {
-        img.onclick = () => {
-          const widthMagnification = document.body.clientWidth / img.width
-          const heightMagnification = document.body.clientHeight / img.height
-          const baseOnWidth = widthMagnification < heightMagnification
-          const magnification = baseOnWidth ? widthMagnification : heightMagnification
+    const markdownPreviewIframe = document.querySelector('.MarkdownPreview')
+    const rect = markdownPreviewIframe.getBoundingClientRect()
+    const imgList = markdownPreviewIframe.contentWindow.document.body.querySelectorAll('img')
+    for (const img of imgList) {
+      img.onclick = () => {
+        const widthMagnification = document.body.clientWidth / img.width
+        const heightMagnification = document.body.clientHeight / img.height
+        const baseOnWidth = widthMagnification < heightMagnification
+        const magnification = baseOnWidth ? widthMagnification : heightMagnification
 
-          const zoomImgWidth = img.width * magnification
-          const zoomImgHeight = img.height * magnification
-          const zoomImgTop = (document.body.clientHeight - zoomImgHeight) / 2
-          const zoomImgLeft = (document.body.clientWidth - zoomImgWidth) / 2
-          const originalImgTop = img.y + rect.top
-          const originalImgLeft = img.x + rect.left
-          const originalImgRect = {
-            top: `${originalImgTop}px`,
-            left: `${originalImgLeft}px`,
-            width: `${img.width}px`,
-            height: `${img.height}px`
-          }
-          const zoomInImgRect = {
-            top: `${baseOnWidth ? zoomImgTop : 0}px`,
-            left: `${baseOnWidth ? 0 : zoomImgLeft}px`,
-            width: `${zoomImgWidth}px`,
-            height: `${zoomImgHeight}px`
-          }
-          const animationSpeed = 300
+        const zoomImgWidth = img.width * magnification
+        const zoomImgHeight = img.height * magnification
+        const zoomImgTop = (document.body.clientHeight - zoomImgHeight) / 2
+        const zoomImgLeft = (document.body.clientWidth - zoomImgWidth) / 2
+        const originalImgTop = img.y + rect.top
+        const originalImgLeft = img.x + rect.left
+        const originalImgRect = {
+          top: `${originalImgTop}px`,
+          left: `${originalImgLeft}px`,
+          width: `${img.width}px`,
+          height: `${img.height}px`
+        }
+        const zoomInImgRect = {
+          top: `${baseOnWidth ? zoomImgTop : 0}px`,
+          left: `${baseOnWidth ? 0 : zoomImgLeft}px`,
+          width: `${zoomImgWidth}px`,
+          height: `${zoomImgHeight}px`
+        }
+        const animationSpeed = 300
 
-          const zoomImg = document.createElement('img')
-          zoomImg.src = img.src
+        const zoomImg = document.createElement('img')
+        zoomImg.src = img.src
+        zoomImg.style = `
+          position: absolute;
+          top: ${baseOnWidth ? zoomImgTop : 0}px;
+          left: ${baseOnWidth ? 0 : zoomImgLeft}px;
+          width: ${zoomImgWidth};
+          height: ${zoomImgHeight}px;
+          `
+        zoomImg.animate([
+          originalImgRect,
+          zoomInImgRect
+        ], animationSpeed)
+
+        const overlay = document.createElement('div')
+        overlay.style = `
+          background-color: rgba(0,0,0,0.5);
+          cursor: zoom-out;
+          position: absolute;
+          top: 0;
+          left: 0;
+          width: 100%;
+          height: ${document.body.clientHeight}px;
+          z-index: 100;
+        `
+        overlay.onclick = () => {
           zoomImg.style = `
             position: absolute;
-            top: ${baseOnWidth ? zoomImgTop : 0}px;
-            left: ${baseOnWidth ? 0 : zoomImgLeft}px;
-            width: ${zoomImgWidth};
-            height: ${zoomImgHeight}px;
+            top: ${originalImgTop}px;
+            left: ${originalImgLeft}px;
+            width: ${img.width}px;
+            height: ${img.height}px;
             `
-          zoomImg.animate([
-            originalImgRect,
-            zoomInImgRect
+          const zoomOutImgAnimation = zoomImg.animate([
+            zoomInImgRect,
+            originalImgRect
           ], animationSpeed)
-
-          const overlay = document.createElement('div')
-          overlay.style = `
-            background-color: rgba(0,0,0,0.5);
-            cursor: zoom-out;
-            position: absolute;
-            top: 0;
-            left: 0;
-            width: 100%;
-            height: ${document.body.clientHeight}px;
-            z-index: 100;
-          `
-          overlay.onclick = () => {
-            zoomImg.style = `
-              position: absolute;
-              top: ${originalImgTop}px;
-              left: ${originalImgLeft}px;
-              width: ${img.width}px;
-              height: ${img.height}px;
-              `
-            const zoomOutImgAnimation = zoomImg.animate([
-              zoomInImgRect,
-              originalImgRect
-            ], animationSpeed)
-            zoomOutImgAnimation.onfinish = () => overlay.remove()
-          }
-
-          overlay.appendChild(zoomImg)
-          document.body.appendChild(overlay)
+          zoomOutImgAnimation.onfinish = () => overlay.remove()
         }
+
+        overlay.appendChild(zoomImg)
+        document.body.appendChild(overlay)
       }
-    })
+    }
   }
 
   focus () {