Where can I find a program with large jigsaw puzzles?

I love jigsaw puzzles, and I prefer the ones that are software programs. I have been dealing with cancer for several years, and over the years I’ve found this to be a very good way to relax and get my mind off pain and worries. I recently bought a new computer and the jigsaw puzzle program is for an old system and will not work on this new computer. The company that made the program no longer exists. I’ve looked at several online jigsaws, but they are all small photographs and tiny pieces. I have a widescreen monitor, and I’m looking for a program that will have or allow photographs which are large, say 800 x 800 pixels in size. This older software program had photographs of this size and larger. Can anyone help?