Hm, the trouble with PNG 16bit is that I don't save a color profile. That means, where ever you load it, like in PS, it will apply its default color profile, likely changing the look of it and possible emphasizing "artifacts" that didn't show earlier?!
...I will explore my options, regarding the profile. I never cared about it, because I actually used it for texturing 3d stuff in the beginning, where the actual color values are taken "as is", you know.
JPeg, yeah, it's bad somehow. Besides weak optimization, it seems like the default library in BlitzMax isn't that good in terms of quality, either, even at maximum, which I'm using.
Anyway, PNG is solid, there is no error in them and the colors will be the original rgb values that you get to see in Verve, while Verve will let the monitor's profile dictate the translation, as far as I can tell. Try switching profiles in PS and see, if it makes a difference!