found these couple of nice pictures: transformers by ~wanbao on deviantART Optimus Prime wallpaper by ~Tamarrion on deviantART Transformers by =An1ken on deviantART
The third one is truly amazing, I've seen it before and the only minor complaint I can think of is ...Bumblebee doesn't seem right. Har har. No seriously, awesome! I'm not too fond of the other two. While the first one looks pretty good at first, it's 'just' a whipped up photoshop of a scene in the first movie (Optimus vs. Bonecrusher I believe, not 100% sure anymore), and judging it as a photoshop, it suddenly isn't a very good one anymore. The second one is just a panel from one of the TF movie comics with some b/s text added..not too fond of it. edit: whoops. My bad. Didn't click on the link for the 3rd pic so I thought it was something else. The original artwork is much bigger, with a whole street and Megatron attacking Prime..it seems this 'artist' just took a part out of it and added some stuff like flashes and gears-looking things. Which look pretty good, they just don't really make sense and with the right tools might even be made in a simpler way than expected... The original artist is Alon Chou, and the piece is named 'Transformers - Death Blow' http://www.alon.tw/cre/cre_transformer.html
i like the first one myself, apart from the scale being wrong, look at the size of the cars compared to prime! still though, at least it gives an idea of what kind of scale devastator would be..