You can download the trial version of photoshop and use it for 30 days free. After that to continue you can buy it, un-install and re-install or download a keygen via bit-torrent, depending on your moral leanings.
I don't know what GIMP's like as haven't used it before, but Photoshop requires minimal editing and adds a nice stroke outline to the image.
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Dinosaurs had eggs bro, the chicken came way later.