This is awesome and inspiring. I'll probably use this in a future project.

A few questions:

1) How do you plan to monetize the service? Always important to ask of free services so I don't get blindsighted later. :)

2) How often are new images added? Is there a process to go through to request specific images/themes being added (perhaps for a fee)?

3) On the "For Designers" page I see that every image is a vector and scalable -- do you plan on offering a few separate PNG downloads for things like small, medium, large? Obviously people can resize things manually (or, at least, I assume they can losslessly resize PNGs without photoshop), but it might be a nice quality of life improvement too.

Sorry if these are answered in an FAQ or something in the footer -- with infinite scroll I can't ever get down long enough to see what's actually in it. :P