Paint Shop Pro (at least in version 8 and beyond) has its own
image curl tool; you won't need any filter or plug in to do it
Open your image and make it the final size you would like it
to be. Promote it to a layer instead of leaving it as the background.
The page curl tool is under Effects, Image Effects:
Select which corner you want to work with by clicking the box
bottom left. Then you will choose the color of the back of the
image for the curl, the color for the background if any (choose
transparent if you will be exporting the image to a layout) and
the angle and size of the curl itself. You can move the flowery
shaped dot on the image to see the various changes it produces
in the curl.
Click okay, and then you can do another corner if you like:
And now you have your final curled edge to export to your layout: