To install a plug-in on a Mac, download it or copy it from the installer disc it shipped with and then drag it from wherever it's saved on your computer into the Plug-ins folder (see Figure 19-1, top): Adobe Photoshop CS5/Presets/Plug-ins. (You can also store plug-ins elsewhere as discussed on Guides, Grid & Slices.) On a PC, download the plug-in or copy it from the installer disc. It should be an .exe (executable) file, so you can run it to install a program. Simply find the file on your computer and double-click it.

Figure 19-1. On a Mac, you can install a plug-in manually by dragging it into Photoshop's Plug-ins folder (top) or by using the installer provided by the folks who made the plug-in (bottom). On a PC, simply run the plug-in's .exe file. If you have trouble installing a plug-in, contact the person or company who created it for help.