Um, a lot of that isn't really true. You said you replaced some portraits and that it freezes when you try to go to the character select scree, right? That probably means your common5 or sc_selchar (whichever you use) is too big. When you put the CSPs back in, make sure that you index them (in gimp it's in image>mode>indexed, i dunno about photoshop) and just make sure that it's smaller than the default.
Also, just to clarify a few things...
-If your SD card isn't 2 gig it won't freeze, Brawl just won't recognize any of the files on it
-CSS and SSS need to be smaller than the original, that's why you should index the images you add to them. If you do that, you should have no problems.
-If Brawl freezes before you get to the character select screen, it's almost always a problem with the select screen.
The thing was, I downloaded pictures from someone else, who's files were working for them.
Size was correct, color, and everything.
Which means they should've worked.
But they didn't.
And I always thought over 2GB froze... my bad.