Question
 

Is there a program like Adobe Photoshop for Linux?

The Gimp.

For more info on software that you are interested in you can always check:
www.freshmeat.net
Search is a function on that site, and reveals some great applications that you might be interested in.

Cool

The Gimp
 

I found The Gimp very hard to use.

It has a learning curve, yes, but no more than Photoshop. There are other tools out there for basic photo manipulation which have a lower learning curve, but when looking for a free (meaning, not stolen) high-end photo manipulation package, Gimp is the way to go.

and you can re-map the Gimps keystroke combinations to more closely match photoshop.

You could also look into running Photoshop under Wine.

But personally, after a while, I came to prefer working with the GIMP.

slight