Paint Shop Pro's native format for preserving all image data such as layers, alpha channels, and all the work you've done, is .psp. If for any reason you change your mind about something, the undo feature will allow you to back up and redo anything - even restore something you've deleted. Paint Shop Pro has unlimited undos.
Most tutorials will instruct you to save your final image by first merging the layers, then saving as a tube, a JPG, or a GIF. This is particularly true when preparing to animate images. Before you merge all the layers, use the File/Save Copy As to save a copy of your finished work in PSP. Or first duplicate the finished image, save the first as a PSP file, then work from your duplicate to make copies for animation or cropping and saving as JPG or GIF.
Saving Rule: Save your work in psp format, then duplicate, then close your psp file with all your work preserved, then merge your layers on the duplicate psp image. NEVER merge all the layers on your working copy. Once you merge all layers and close your file and exit from Paint Shop Pro, you can no longer undo anything on your psp file! All the storage of data is lost once all the layers are merged, saved, and the file is closed. But if you saved a copy, all the data is preserved. The File/Save Copy As is extremely important.
Another tip: When working on a long and complicated tutorial which calls for merging layers on one object or more, use the File/Save Copy As, and name the file numerically and save in psp format. For example, let's say you're creating a bouquet and each flower has several parts consisting of petals, stem, and leaves. The instructions will say to toggle off the other layers, then merge the petals, stem, and leaves and rename the merged layer to something like flower 1. Remember this: BEFORE you merge, save a copy of your work using File/Save Copy As as bouquetflower1.psp. Then when you add layers for the second flower, and again BEFORE you merge those layers, save another copy of your work using File/Save Copy As as bouquetflower2.psp. This will not change the name of your working copy [which would be something like bouquetflower.psp] which will not be affected in any way yet will save a psp file with all data intact.
When you have finished working on your bouquet.psp, you may have several saved psp files for one project - all with your work preserved along each step of the way allowing you to back up at any stage and undo or add something. Most of the time saving once in psp format and then using the File/Save often during a tutorial is all that is needed and all the saved psp files from various stages won't be needed IF you remember to SAVE COPY AS, then duplicate it, then do your final merging last time. Now you'll have a copy of your bouquet.psp on your system with all your work preserved.
Description of the Three Save Options:
1. File/Save option saves the image in the original format. If for instance you open an image, add something to it and then use the Save option, you will overwrite the original image.
2. File/Save As option saves the image to a NEW file and does not overwrite the original image.
3. File/Save Copy As option copies the original image, but does not affect the original image.