This is my third, and because I haven't seen an instructables about how to do it, I decided i would post about it.
For this you will need:
A small sheet of plywood or scrap. (I used 3/8th" which was definitely overkill and cost me a jigsaw blade)
An image that you want to make into a puzzle,
A few extra blades,
A little bit of patience
I got my jigsaw (also known as a scroll saw) to do simple work with aluminium, using it as a cheap alternative to a bandsaw. besides needing to frequently replace the blades, it has slowly won me over by being able to cut tight curves and by the smaller kerf size(more on kerf later).
Step 1: Gluing Down the Image
Spray adhesive isn't necessary, any glue that will hold the paper to the wood is alright. I prefer spray adhesive because it lets me finish this first step in two minutes, rather than requiring me to put down the project for an hour.
Print your image at the size you want, and line it up on the scrap so that your entire image, and however much background you want is over the scrap of wood. You will trim the paper and the scrap in the next step so don't worry about it yet.
Next glue your image to the plywood backing. I had a lot of room on this scrap for this image so I just sprayed a bit of the adhesive on the wood and then pressed the backing down onto it with enough room on all sides for the background.