Quotes: Disney Owns This Trope

"The Photoshop trademark must never be used as a common verb or as a noun."

Always capitalize and use trademarks in their correct form.

Correct: The image was enhanced with Adobe® Photoshop® Elements software.
Incorrect: The image was photoshopped.
Incorrect: The image was Photoshopped.
Incorrect: The image was Adobe® Photoshopped.

Trademarks must never be used as slang terms.

Correct: Those who use Adobe® Photoshop® software to manipulate images as a hobby see their work as an art form.
Incorrect: A photoshopper sees his hobby as an art form.
Incorrect: My hobby is photoshopping.