Photoshop is often considered to be the best desktop raster graphics imaging editor software on the market, with zillions of features, not to mention a massive array of filters available online and from retail outlets. Many graphics artists come to rely heavily on a set of Photoshop Plugins to do the work they do, and may recommend these plugins to other artists.
The GIMP (GNU Image Manipulation Program) is a free, open-source raster graphics imaging editor that is quickly becoming a strong challenger to Photoshop. GIMP may not yet be able to replace Photoshop for everything Photoshop can still do. But we can take one thing off the list (well, sort of). GIMP can, in fact, use Photoshop Plugins with relatively little effort, with the use of the GIMP PSPI plugin from Tor Lillqvist.
Because Windows and Linux have different issues getting PS plugins to work in GIMP, I have tried to expand the areas where the OS makes a difference. Otherwise, the processes described herein are really much the same, no matter which OS you use. However since I do not own an OSX computer I cannot vouch for this process on that operating system.
Step 1: Assumptions, Prerequisites and Caveats
This tutorial assumes you have a fair knowledge of how to copy, move, and paste files in the Windows Explorer, or in Linux, whichever you favor.
This tutorial does not assume you know how to use The GIMP, but it does help if you have experience with it.
Linux users must have wine (WINE Is Not an Emulator) installed for pspi to work. It will be required for any plugin that, under Windows, would need to be installed. It may also be required for any plugin that has a dialog window. This is many of them. It's possibly even required even when the first two conditions aren't met. Remember, these are plugins designed for a Windows application. Just get and install wine, and run winecfg to set it up.
Not all Photoshop Plugins will work 100% with the GIMP PSPI plugin. I have tested a few, some of which work perfectly, and others which don't work at all. So, the standard disclaimer applies: YMMV, TANSTAAFL, and all that jazz. And my standard disclaimer: if anything you do while following these instructions destroys, injures, or emotionally scars anything or anyone, that is not my fault... make backups, save frequently, and use plugins responsibly. Thank you.