Since I don't use (or know Adobe CS) I can't directly answer the question about a contrast adjustment for Adobe. But, in The GIMP 2.4 that feature is under the "colors" tab in the image window. You can adjust the constrast and brightness of the layer selected. I use it to bring out detail in shadowed or bright areas. I'm sure Adobe CS has a corresponding feature somewhere.........I just don't know where it would be or what it might be called. Lana can probably expand a little more on that subject than I can.
Now, I have a question (probably for Chosen Few) relating to resolution of an image not at the required powers of two. I understand the using the canvas to "fill" in an image that is not at the power of two deminsions. And I've done that on a few occassions to get an undistorted image........mostly if I just want to pass the image to another as a texture (like a snapshot taken and saved to my drive at my resident resolution which is 1280 x 1024). If I didn't do that then the image would be distorted when I passed it to the person until it was mounted on a prim and adjusted to the proper proporations. But, if the texture is intended to be mounted on a prim to be displayed as a picture or any texture that requires proper proportions, what is the difference in adjusting the texture repeats and offsets to get the proper placement and adjusting the prim to get the same results? In my mind, you are still "stretching or squishing" the texture to get the proper diminsions........one way you are doing it by adjusting the texture to fit the prim and the other way you are adjusting to prim to fit the texture. Either way you are stretching or squishing the texture of the image.
I'm not disputing the procedure at all. I just have a problem seeing the difference in the two methods. Thank you for any answer that will help me to understand.