I created a texture for a 3d mapping. I made it joining the images (photos, that had been taken during different lighting conditions). Every horizontal image has slightly different color, brightness and contrast. My question is how to unify them?
You're looking for "Match Color" under "Image" and then "Adjustments."
You'll need two images though, so save a copy of the image, called something like "Original_Colors.jpg" and then work in a second one. There's a really good tutorial here:
In your case, you won't have to be super careful with the selection areas, so this should be a very easy thing to accomplish.
With about 30 seconds work, I made this from your art:
With a little care and attention, you should be able to do much better. Good luck!