Balance is key. The club has a sub, right? Use a table (I can help you with the coding) and feature nine pictures. Four lineart, four colored lineart, and the wildcard to whichever medium has the most meritorious dev for the tie breaker. 3 times three ought to assuage your OC nature, and the table will keep everything nice and neat. Just a thought, don't know if that's more complex than you want to get.
You might also perhaps consider a percentage. Dunno how many entries you normally get...but find out whatever percentage 4 is, then use that as a guide. Next month maybe you get only half the entries...so halve the featureds.