Forum | Appery.io

I noticed on a theme I imported I can add images to the right of the css when viewing the theme. However, when using the ios-like theme provided by appery there is no images area. how do I add theme images?

I did notice that I can cheat by adding an image to images area via a fake edit of existing image. However, they do not appear to relate to theme.

I am trying to add a button icon via css which is not working (although works on other app with image added via theme)