If you save an image to your computer, it is saved as a JPG image. There are thousands of viewer that will load JPG inages. There is one that comes standard with Windows, and I suspect there is one on a MAC. So no special viewer is needed
If you do not have an image view on you computer that are many free ones available. I personally use Irfanview a free download
I keep all of the documents images to support my genealogy work on my computer. I "print" every thing to a PDF printer (there are many free ones) and maintain them as PDF files. In my opinion PDF are easier to use the JPG images.
Again there are many free PDF writers and viewer.