www.adobe.com

The market-leader in digital imaging software probably needs no introduction, probably needs no link either, but this list wouldn't be complete without it...

www.altamira-group.com

Home of the Genuine Fractals software, a compression and scaling tool...

www.andromeda.com

Andromeda Software produces several photoshop plugins. Some are more useful than others. Mac and Windows versions are available...

www.camerabits.com

camerabits.com produces the quantum mechanic noise reduction plugin and photo mechanic image browsing software. Not the quickest software, but available for mac, as well as windows and support of high-end cameras...

www.colormechanic.com

Digital Light & Color produces software for photography including a plugin called Color Mechanic Pro, which incorporates a different-than-usual approach to selective color corrections...

www.extensis.com

Extensis is a creator of several plug-ins, also for QuarkXpress. Most plugins are available for the Mac and Windows platform...

www.jasc.com

Home of the (in)famous PaintShop Pro (a.k.a PSP). Several other software-titles are available as well, though primarily windows based....

www.macromedia.com

The makers of the well known Flash player. Several software titles available, some of which support photoshop plugins, predominantly aimed at web-publishing...

www.microfrontier.com

MicroFrontier makes the ColorIt! image editing software which also supports photoshop plugins. In addition they develop several other digital imaging software as well...

www.powerretouche.com

PowerRetouche creates Photoshop compatible plugins most of which are specifically aimed at digital photography. Plugins are available for both Mac and Windows...