Yes. I have Adobe PhotoShop 5.0, which runs perfectly on my 366 MHz clamshell iBook. I have a 1 GHz AlBook as well, which runs both CS3 and Gimp. I got both for free by having them pre-installed, and I would otherwise never have bought them. I definitely prefer 5.0 for what I do, even though it's occasionally buggy using the version of Classic Envir0nment in Mac OS X 10.1.
What kind of pictures do you work with?
I use PS CS1, although I have had CS3 installed so I could use DW. I do all my photo editing and cover designs on CS with my eMac and now recently revived G5. Check out some of the simple stuff I've done:
I did these covers, they should all be published this year (with the exception of the Body Rentals Novella) I've been writing that one for three years now. My first short story should be published in a month or two. I am quite proud. If you are interested, my writing blog is at http://article94.blogspot.comLooks good. I take it your an author? Or an illustrator for one perhaps?
I use Photomatix Pro to convert CR2 RAW files into a TIFF and then edit in PS, if that helps you at allI use Photoshop CS on my PBG4. One of the problems is I shoot in RAW/NEF and have to convert the files into DNG inorder to do any editing. And many times I have had lots of photos that need editing. I'm going to have to upgrade to an Intel soon.