define a brush
step one
first, open up your image pack in psp, i'll be using this pack of hearts;

step two
choose the image you would like to make into a brush. select your selection tool (you can use the lasso tool or the rectangle tool depending on the shape of your brush)

step three
go to your paintbrush tool and click the picture

step four
go to the icon that looks like a paintbrush with an outline around it

step five
you'll then see a textbox pop up, rename your brush and press ok and voila!