I am using 2 500K bitmaps in to display images on my WiX dialogs.
They dramatically increase the size of the installation package, and what is worse - it looks there's no way to package them as a part of a .cab file since they're <binary>-es in the WiX terms.
So, I thught, is there any way to use other file formats for bitmaps or WiX is tethered with BMP? Ideally it would be greate if there's a way to use .png format since it comes with a looseless compression option.
The Windows Installer documentation for the Bitmap control states that the image should be a "bitmap" -- presumably a .BMP file -- or a JPEG.
You have to remember, when working with WiX, that it's based on Windows Installer. This means that any limitations in WiX are often caused by limitations in the underlying Windows Installer implementation.
.BMP files can be RLE-compressed. I don't know if they support any other compression algorithms.