Theres some really great programs on the Amiga for graphic work, like Photogenics, ImageFX, Art Department Pro, ArtEffect, FXPaint, TVPaint, XiPaint, Perfect Paint, Personal Paint, Deluxe Paint, Brilliance.
Some of these are more out of date than others, but I personally really like and still use Personal Paint, Perfect Paint, TVPaint and Photogenics.
I am familiar with and use Photoshop 7 and Paint Shop Pro on Windows, but I still use my Amiga for gfx if I do any gfx.
None of these programs compensate for my complete inability to draw, though ;-)