The Photoshop trademark must never be used as a common verb or as a noun. The Photoshop trademark should always be capitalized and should never be used in possessive form, or as a slang term. It should be used as an adjective to describe the product, and should never be used in abbreviated form. The following examples illustrate these rules:

Trademarks are not verbs.

CORRECT: The image was enhanced using Adobe® Photoshop® software.
INCORRECT: The image was photoshopped.