If you like the GIMP for image editing and have a Mac OS X machine, try Seashore. It does the same basic stuff that the GIMP does but in a Cocoa interface and only about 6MB (compared to 61MB for GIMP).

Seashore works decently and I like it because you don’t have to go through the X11 thing to emulate X windows. I used Seashore until I discovered Mac Paintbrush. Paintbrush is much faster and satisfies my rudimentary needs.

Just note — if you want to save stuff and preserve your layers, be sure to save it as GIMP .xcf format. I thought it might do layers for PNG but maybe only the old Macromedia Fireworks program can do that. I loved Fireworks.

Get Seashore
Get the GIMP
Read about Paintbrush