I think this kind of utility is a really nice idea and could see a great number of uses derived from it.
While creating a utility like this in DesktopX would make the gui creation easier and overall design much nicer, it would be very difficult to implement the features you're looking for natively. DesktopX unfortunately does not include support for encoding .png or .gif images. DesktopX is very flexible though, so if there were some kind of library that offered support for these file formats (allowing free distribution, of course), it would be a (somewhat) trivial task to throw this widget together.
A number of years back in college I actually wrote a graphics app in c++ that included support for encoding and decoding bmp,gif (+animated),jpg. I'd have no problem using my code from this, but unfortunately the drive these (and many other) apps were on is toast (doesn't even spin up).
There is, however, a utility for compiling images into bit strips, that might prove useful until creating the image compiler as a widget became feasible:
I'll see if I can find a free library offering png+gif support that might make this project doable and post here if I do.