diff --git a/lib/pen.js b/lib/pen.js
index 7a5585c..09e4569 100644
--- a/lib/pen.js
+++ b/lib/pen.js
@@ -184,35 +184,27 @@ export default class Painter {
       case 'image': {
         // image的长宽设置成auto的逻辑处理
         const ratio = getApp().systemInfo.pixelRatio ? getApp().systemInfo.pixelRatio : 2;
-        if (!view.css) {
+        // 有css却未设置width或height，则默认为auto
+        if (view.css) {
+          if (!view.css.width) {
+            view.css.width = 'auto';
+          }
+          if (!view.css.height) {
+            view.css.height = 'auto';
+          }
+        }
+        if (!view.css || (view.css.width === 'auto' && view.css.height === 'auto')) {
           width = Math.round(view.sWidth / ratio);
           height = Math.round(view.sHeight / ratio);
+        } else if (view.css.width === 'auto') {
+          height = view.css.height.toPx();
+          width = view.sWidth / view.sHeight * height;
+        } else if (view.css.height === 'auto') {
+          width = view.css.width.toPx();
+          height = view.sHeight / view.sWidth * width;
         } else {
-          if (!view.css.width) {
-            width = Math.round(view.sWidth / ratio);
-            if ((!view.css.height) || view.css.height === 'auto') {
-              height = Math.round(view.sHeight / ratio);
-            } else {
-              height = view.css.height.toPx();
-            }
-          } else if (view.css.width === 'auto') {
-            if ((!view.css.height) || view.css.height === 'auto') {
-              width = Math.round(view.sWidth / ratio);
-              height = Math.round(view.sHeight / ratio);
-            } else {
-              height = view.css.height.toPx();
-              width = view.sWidth / view.sHeight * height;
-            }
-          } else {
-            width = view.css.width.toPx();
-            if (!view.css.height) {
-              height = Math.round(view.sHeight / ratio);
-            } else if (view.css.height === 'auto') {
-              height = view.sHeight / view.sWidth * width;
-            } else {
-              height = view.css.height.toPx();
-            }
-          }
+          width = view.css.width.toPx();
+          height = view.css.height.toPx();
         }
         break;
       }