Graphics editing program developed and published by Adobe Systems. So ubiquitous its use in photo manipulation that it birthed term "Photoshopping".
Photoshop 7 was the last of the breed of release version naming before Photoshop 8 was unleashed under the umbrella packaging of Adobe Creative Suite (CS).
Current versions of Adobe's Photoshop are known by their CS suffix. Photoshop CS6 is actually the thirteenth release of the photo and graphics editing program.