Photoshop can import vector-based files, but it is not a vector program, it is a raster program. You'll want Adobe Illustrator. Photoshop will (should) allow you to choose size on import, and will retain the quality of the image if its a true vector image, but other than that it's going to end up in a raster format.

It all depends on the order in which you setup your pedals. Keep in mind that the distortion pedal distorts any audio signals traveling through it. What you need to do it have your guitar go into the input on the distortion pedal or wah-pedal, then the output of that pedal will go to the input on the Boss RC-2 Loop pedal, and the output will go to the amp.

Basically, just keep the effects pedals connected to your guitar before the Loop, so you can choose to record a clean loop or a distorted loop, then play over it however you want.