It's an oversimplification to say it this way but the best way to think about it is that the AppPool is a pool of AppDomains.  All of these AppDomains run within a single worker process (w3wp.exe).

What is Application Pool in IIS and Asp.Net?
If I save my file from Photoshop as a Photoshop EPS is that going to be okay as a vector across the board (ie will it be resizeable in whatever it's opened in)? I know if you open a .psd in Photoshop and resize the image, it holds it's quality, so that's fine, but when people need an EPS file because they might want to print it on the side of a building one day (or whatever) is a Photoshop EPS going to be okay? Or is there something else I need to be doing? 

All my designs are always vectors within Photoshop, so text/shapes/designs done with the pen tool - I just need to know that they'll still be a vector for people who don't have Photoshop and can't open it in there to resize it.
