I have an Omnitech 7" 16:9 digital photo frame, and the manual says the optimal resolution is 480(RGB) x 234. Where can I find a good, free program with no limitations(i.e. no watermarks, etc.) that I can use to resize pictures without cropping or stretching to fit this resolution? I want some pictures shrunk and others enlarged, but of course I want to keep their proportions the same, lest they be contorted and deformed beyond recognition. Also, I'm assuming that this is in pixels, right? Also, are all 7" widescreen 16:9 frames the same when it comes to resolution (480 X 234)?