style: 更新图片预览组件的边框样式

src/lib/editor/imagePreviewPlugin.ts

@@ -27,8 +27,7 @@ class ImagePreviewWidget extends WidgetType {
 		img.style.display = 'block';
 		img.style.marginTop = '8px';
 		img.style.marginBottom = '8px';
-		img.style.borderRadius = '4px';
+		img.style.border = '1px solid #e5e7eb';
-		img.style.boxShadow = '0 2px 8px rgba(0,0,0,0.1)';
 
 		wrap.appendChild(img);
 		return wrap;