New pro/con: Many plugins and scripting interfaces available
Agreed: "Extensive featureset, comparable to Photoshop"
Agreed: "Extensive file format support"
Agreed: "Supports read and write of PhotoShop .PSD file format"
Agreed: "Available for UNIX/Linux, Mac OS X, Windows"
Agreed: "Open source application"
Agreed: "Free alternative to Adobe Photoshop"