Ron- You can adjust the number of pieces to fit your skill, time allowance, and screen size. There are at least two puzzle sites. I avoid jigsawplanet and only play Jigsaw Explorer. On that site, if you click the timer, it stops the puzzle. You can reopen that page and resume whenever you want.

I saw puzzles posted on YT and didn't give them much thought until one day I decided to give it a try. I discovered I liked them but they were too simple. Figured out how to adjust them up and I was hooked!

As stated above, I don't care for the kind of image in the OP, but I know some do- probably the same folks who like the all-white puzzles.