When you save a mask to an alpha channel within a .PspImage image, you can load that mask from the alpha channel into the same image or into any other image.
To load a mask from an alpha channel:
On the Layer palette, click the layer you want to mask.
Choose Layers > Load/Save Mask > Load Mask From Alpha Channel to open the Load Mask from Alpha dialog.
In the Document drop-down list, select the image which contains the alpha channel you want to load. (Choose from open images with existing alpha channels only.)
In the drop-down list below the document name, choose the alpha channel which contains the mask you want to load.
In the Orientation group box, select from the following options: Fit to canvas, Fit to layer, or As is.
In the Options group box, select whether Paint Shop Pro hides or shows pixels surrounding a loaded mask that is smaller than the current image canvas. Choose Hide all mask or Show all mask. To invert the transparency of the mask image, mark the Invert transparency check box.
Click Load.
Paint Shop Pro adds the mask layer and the selected layer to a new layer group. The mask layer applies to the selected layer only. To apply it to all underlying layers, drag it from the layer group to the main level.