Well, halfbrite is sort of an extension of the original ILBM specification, so I guess some software doesn't know about it. I take it you don't have UAE installed? Might be a good opportunity to set it up and play around with a few programs. PersonalPaint should do a good job, does a lot of what DPaint can do (though not all), and can export a lot of formats including JPEG and BMP. It's freeware now AFAIK...
