I thought about reviewing every single cover solicited, but that would take way more time than I've got to give this, so I'll just tell you the general reasons why the covers I don't mention below were ineffective:
A) Too artsy. This is especially a problem with Jonathan Hickman's books A Red Mass for Mars and Pax Romana. The cover designs are beautiful and serve Hickman's brand by giving his books a distinctive look, but if you don't already know his work, they don't really tell you what the books are about.
B) Too pin-uppy. There are several with this problem, but Spawn #177 immediately comes to mind. All the cover tells you is that this is a Spawn comic. If you've already been buying the series, you're informed that this is the next issue, but there's no reason for a new reader to pick this up and give it a look.
C) Just not my taste. And there's the hitch. Some of the covers give a good try at teasing you about what's in the issue, but taste being subjective, I'm not going to be attracted to each image. Fearless #2, for example, shows the hero surrounded by syringes. That might be a compelling image for some, but it's a turnoff for me. Same with the whatever-that-is coming out of dude's mouth on the cover for Overman #1. Totally not fair, but there you go.
These are the ones that make me want to plop down my money:
Bonds #3: Even though it's the last issue of a mini-series, the
Cryptics #3: I'm a Steve Niles fan, but even if I didn't know this was one of his books, those monsters and penguins make me giggle enough that I'd want to open the book and see if there were more laughs.
Fantastic Comics #24: I don't know that this is for me, but the pulp-action cover makes me want to find out. Those red sandals are goofy though.
Steve Niles' Strange Cases #3: Again, Niles' name is a selling point, but even if I didn't know who he was, the Yeti would have me.
Tim Sale: Black and White:This is a pin-up, but it's for an art book, so it's appropriate. Actually, even if it was for a comic, my jungle girl fetish is strong enough that I'd still want it.
So, what about you? Which Image covers for December make you want to buy the books?