Hello.

I'm really grateful for help past and present. I'm sadly needing to make sure if my game ends up somewhere else on release, that I have a few back up processes in place. One of those is to tag much of the graphics and also have my itch.io link show up on many of the graphics.

 It's not a pleasant thought after all these years. It seems to be the safest way due to some of the stories I've heard from people who have had their game stolen and reverse engineered. The main aim is to make sure anyone who finds my game outside of Itch.io will know who the original creator was. 

What are your thoughts on the idea, and how far should I go?

You are trying to perform watermarking, the first of two kinds: visible and invisible watermarks. Invisible watermarks are used for hiding information that can identify the buyer of your product for the purposes of preventing copyright infringement. These sorts of watermarks are hard to find and hard to remove without breaking the original work.

Visible watermarks are the opposite - very easy to spot, but also easy to remove. And considering these are game assets we’re speaking of, a determined attacker won’t have to put in much effort to crop it out, make some section transparent or apply some subtraction operation. There’s a smaller chance if said graphics appear somewhere less obscure than, say, the main menu, but then the player is also less likely to see it.

So YMMV.