This is some really peculiar behavior, what we do is simply set the provided file as the image, we do not modify it in any way. I cropped the image to 16x16px and tested it in all major browsers and things seem to be working fine with me. You can find my test page attached as well as screenshots from the different browsers. Can you confirm you are using the latest version of the controls? Is there any custom CSS on the page and if so - what happens if you remove it? Is it possible that the file you are using is somehow corrupt - please try creating it anew and see what happens. What happens if you set this image as a background image to a simple table cell outside of the RadWindow?
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