Is it possible to merge texture images without baking them?

In the regular Blender Internal render engine (which is what I’m interested in right now) there is a baking option for “textures” which when selected will bake only the color information of the texture layers of the material. I really hate that these have to be baked and undergo an entire rendering process for this. Is there any possible way these could just simply be Open GL baked or is there any way possible to simply merge two generated images in Blender without baking them? Thanks.

greetings,

I would also really like to know the answer to that question.
I created several space ships and being a beginner with blender, I did not care about materials or textures. I just used UV-mapping to assign several images per ship to different parts of the model.

now when I want to use the model in Unity for example, there are several textures attached to the imported object which is bad for performance. is there no way to merge several used uv images to one image without using materials, textures, bake…?