Load image form data, composite and blent them -> on Linux

[georgbachmann]

I have some images in a sqlite database. I read the raw-data from those images, and not I'd need to composite them. So place one image an certain coordinates and the other at different ones and then create a new image out of it. Then I'd also need to blend an other image onto this image... Would be an easy task using CoreGraphics, but I need it for Linux.
Is GPUImage2 the right solution for my problem? Or can anybody point me to better alternatives for that task?