New to Shopify and quite a novice with this type of thing however, Is there a way to add a Picture as a background to individual pages. Example: Can I add a picture of a reaper to my reaper products page, and a christmas picture to my christmas page etc etc?
You would need to edit the code to set a new background.
It might be possible to set a different background for home and product pages but I think it's way too difficult to set a different one for each individual product as each product page inherits from the product page mother layout.
Would've been an interesting feature, I agree. Sadly Shopify hasn't implemented anything of the sort yet. But it is still possible if you know how to code it yourself Amd changing the background to a picture to apply everywhere is pretty easy actually. I know it's not exactly what you're looking for but it's a starting point.