I would like to change the black hole texture from blue to red. I have found the files I need to modify, but I have no idea how to actually change the colors. I do not know how to preserve the gradient of the texture (it goes from blue and changes to white at points, and I would like to preserve the change to white). I can change the color of every pixel of a certain color, but this does not help me preserve the gradient (I was flipping the red and blue color values while deleting the green and it goes to magenta, not white). Also this is very tedious if I want it to look good. Is there a better way to do this? I have both Photoshop Elements 2 and GIMP.

I'm taking Graphic Design at high school, so I know how to do this.

Use the color replacement tool to replace all colors with black, (making it very black and white), then make a new layer with your color, then setting that layer to Overlay or Multiply.

Color replace did the trick. It looks very cool. Thanks!