Vizard automatically scaling image to an aspect ratio of 1:1

[Erikvdb]

OpenGL limits the texture resolution to always be a power of two (i.e. 16, 32, 64, 128, etc.). However this is not restricted to aspect ratio, so you can have 512x256 rectangular textures as well.

Actually I read that in newer versions of OpenGL, non power of two (NPOT) textures are supported, but I know too little about that to come up with a possible solution for you.

My solution would be to find a Photoshop script that automatically places and fits every image in a 1024x1024 texture, and then edit the texture coordinates in Vizard to get the result you want.