Straighten a Crooked Photo and Fix Skewed Perspective with Paint Shop Pro

If you like, you can enable grid lines. For this image I have entered 3 in the grid lines box. As you can see it adds grid lines to the rectangle which can be helpful in getting the control handles aligned with the image we are going to straighten.

Then go to your image and move the four corner points of the control rectangle so that it aligns with the building in your image. Make sure the top and bottom lines of the rectangle are aligned with part of the photo that should be horizontal, and make sure the left and right lines of your rectangle align with the sides of the building.