I really like that pic you did for your bf and if creatures have 'particles' and its causing some conflict when you open the screenshot in an editing program you can go into Model Control under View and un-check Particles, and for base layers (say Skarr had a glowing aura), you save the creature without its particles and without the aura (via the check marked boxes in the white box in model control as a BMP. and then you uncheck the parts of it that are the actual body and you check mark the auras and then save it as a PNG., then you open each screenshot seperately, create a layer, post the aura on, then add another layer, copy the next aura screenie, and paste (i always save each aura effect as its own screenie but im not sure if it effects the picture in any way).
This is the guide i followed, it will make a whole lot more sense then my rambling
http://forums.wow-petopia.com/viewtopic.php?f=4&t=13857