I've done it for you Saga.
It's difficult unless you have some sort of photo editing software, but what I done is - copy the picture off Preston's site and loaded it into my Photoshop Elements. I mostly adjust the size, it doesn't need to be big, 200 x 200 pixels is plenty, then save it to your disc where you'll find it in a minute.
Now, when you're creating the review thread, it says that the current picture is blank (unsurprisingly) but underneath there is a box "Upload new image" and an area alongside which says "BROWSE" - click on the Browse. That will show your disc contents, just find the image you created and it will load it as the image to use for the product.
Simples! Sorry I missed it earlier, but in future best to speak to the organ-grinder direct (me).
Who mentioned a monkey, Geoff?
I didn't. :wh
Now you should go back to it and edit your post awarding it some points and don't forget to click the little box with it that will show the points.
Nice review and write up, Mr Lout, glad to see someone's getting the hang of it.