Photoshops existed before the application, and were used as verbs, I’m sure.
"I ran out of solution… gonna have to photoshop these last rolls! 
Same as Wes, Gimp and Inkscape. I have used others, for money. And just today I recommended against buying Photoshop; most image editing tasks are solved, and the latest Gimp looks just like the Photoshop everyone used in college 10+ years ago.