To me it's good as it is right now... its simple and thats the best. To much would make it difficult to see, what is on the site... but if rest of the members want more pictures... i have an idea.
May be one think... just for example. You can put the random pictures under the Photo of the week... like 4 from left to right... and you can put the Top rated, just right there where the Random's are right now... may be also 4 pictures... the 4 best.
or the opposite... you leave the random pictures on the left and put "Top rated" under the Photo of the day... also 4. Just small pictures, just like the random's
But it shouldn't be to much... keep it simple as it is...
You can try it out and show a sample... just to see how it is for our eyes.