in this tutorial, you'll learn how to add a gradient, or a series of slowly blending colors, onto an image.

I'm going to use this image of Craig Owens. if you'd like to paste in your own, that's fine.

first, go to adjust - hue and saturation - colorize (shift+L)

match your settings to mine to get a totally black and white image.

now create a new raster layer:

fill it with the gradient you want in your image. any gradient will do; you can choose from a variety that are already in Paint Shop Pro, or play around and create your own. there are also great ideas for gradients, or ones you can cut and paste in here on the site. use the paint bucket to fill your new layer

now, set that layer to overlay at 100% opacity.

your new image should look something like this