Where do I go to change my default photo viewer?

Easiest thing is to right click any picture file (jpg bmp etc.) properties and find ~opens with~ near the top, and click change. Pick a program from the list or browse for one. You'd have to do this for each type of file, i.e. - once for jpg's once for bmps, once for png's etc. that is if you want to change each one.

easy. right-click the picture, highlight "open with", click "choose program", select the program, click "always use the selected program to open this type of file", then click "OK"

you will probably have to do this to all of the image types (for ex, you would have to do it once to each of these types of files: jgp, bmp, gif, etc...).