PPaint seems to load images into chipmem, while Brilliance 2 loads images into fastmem, and simply copies the visible part to chipmem, allowing you to work on huge images without ever running out of chipmem.
It does not.
PLease gives reason for your asumption, plus deatails of the system you are running on. (that way I can help you figure out what my be wrong).
First guess would be using personal_agnus_blit.library rather than personal_cpu_Blit.library
Unselect the Menu->Graphics->AmigaBlitter option if selected save settings and restart.
There's certainly room for improvement:
Always. Even Photoshop can be improved :-)
1. Handling of very large images. This is a an absolute must. You MUST add this.
I'd love to take credit for this, but it exists since long before I saw the source code.
4000x5000 pixels was the largest I could get running on my SAM 440
2. Handling 24 bit color images as 24 bit internally and use HAM6/8 for visualizing the image.
This isn't going to happen very quickly, if at all, though never say never, Brilliance 2 was a total rewrite IIRC or is thet TrueBrilliance? not 100% familar with whioch names never even heard of that bit of software til I worked on PPaint.
In my 3.x days my choice was DPaint PPaint ot ImageFX
3. Brilliance 2 has a horizontal interface orientation at the bottom of the screen. This is actually a second screen. This means that the interface will always have the right colors and resolution regardless of the screen mode you're using for the image.
Seem to remeber ImageFX working like that too, it was pretty crap.