fix

weed/images/resizing.go

@@ -19,10 +19,17 @@ func Resized(ext string, data []byte, width, height int) (resized []byte, w int,
 
 	dx := srcImage.Bounds().Dx()
 	dy := srcImage.Bounds().Dy()
-	if width/height > dx/dy { //定高
-		width = height * dx / dy
-	} else if width/height < dx/dy { //定宽
+
+	if height == 0 {
 		height = width * dy / dx
+	} else if width == 0 {
+		width = height * dx / dy
+	} else {
+		if width/height > dx/dy { //定高
+			width = height * dx / dy
+		} else if width/height < dx/dy { //定宽
+			height = width * dy / dx
+		}
 	}
 
 	if err == nil {