[gui]默认支持png格式图片

components/gui/Kconfig

@@ -52,7 +52,7 @@ endchoice
 
 choice
     prompt "PNG image format"
-    default RTGUI_IMAGE_PNG_NONE
+    default RTGUI_IMAGE_LODEPNG
 
     config RTGUI_IMAGE_PNG_NONE
         bool "No PNG image format"