Sorry for the confusing title. What I did was scan 3-4 photos at a time and then crop those photos into new layers per scan and then I combined them all into one PSD. So what I have now are several differently sized images on a larger canvas. This leaves extra white space when I run the Layers -> Files script. So now how can I resize all of the layers and save them as jpegs?
The easiest way to do this is Slices. Although they're not intended exactly for this, they can do it.
Space out all your images, slice with the Slice tool accordingly, then Save For Web, pick a folder, and they'll all march right out as jpegs if you pick the right compression type.
The caveat is that your images will need to be spaced out. Any overlaps and the slicing won't work properly.