My problem is about uv mapping. My model has multi parts. I unwrap my model parts then i create uv map image for every single part. In texture painting mode i painted every uv map image but after paint 3 images first and second is gone. I clicked first image and it's just show black color not other colors that i painted. I solved this by save as image but i have to do for all uv map images Is there a other way to do this ?
As far as I know, you will have to save these manually every time. Blender will discard everything not used, and not saved. Therefore you will have to save the texture, for it not to vanish.
OR you can pack the image into the blend file.
See this post regarding the same subject: