Multi-colored Images

Step one

Locate your image.

Step two

Make or use a gradient. I am using one I created:

Paste the gradient by right clicking and choosing "Paste as new layer" or if you used your own gradient make a new raster layer before doing so. Right now you should only be viewing your gradient and no trace of your image. Set the layer to Lighten at 80% like below:

Your image should look like below:

Step three

Duplicate your base (background layer) and set it to the top as Screen 100% like below:

Your image should look like below: