That freesite will get listed at most places I guess. I see no real rejection reasons on that one.
On a personal note, I myself don't like it when your pictures have different sizes. pe. one is 500px on the longest side while others are 666px on the longest site. If I was you (which I am not) I'd keep the all the same size (again, I'd go for the 666px size rather than the 500px one). That makes it a little easier for the reviewer since he doesn't have to check with every pic what the size is
