I checked the ID with each image I tried, and in each case it was the correct ID as assigned for the background fill of the "Tabs" button.
In addition to the GIF, I tried a PNG (PNG-24) and a JPEG. None displayed as the background pattern in a Windows standalone.
I made a button so that, while in the standalone, I could navigate to my usually non-displaying card on which these images are "imported as controls". All three images, the GIF, PNG and JPEG versions, do appear in the Windows standalone, although, as you can see, it doesn't appear as the background fill for the "Tabs" button.
So it appears images don't work as background fills for Windows standalones, at least for "Tabs" buttons as applied as shown in this screenshot:
Now, Klaus, how do we report this as a bug? Is telling you sufficient? I'm testing this in Windows 7, incidentally. Thank you very much for your help, by the way, Klaus and Jacque.
Thanks,
Steve