Plenty of times we see this kind of drama.
Whether its on DeviantArt, Newgrounds, FurAffinity or some kind of roleplaying group in some kind of social media, there will always be an event where somebody points at something they recognise and call the original poster out on committing art theft.
The usual response being "But I found it on Google Images!" or "If you care so much about your art, make sure it can't be found on Google Images".
Either way, Google Images is usually involved somehow.

So what is this thing called "art theft"?
Well, its when somebody uses a piece of somebody else's art without the artist's permission.
I said "uses". This means things like: Using it as their roleplaying character, in their image edits, as part of their website, as part of their video or just plain copying/tracing it.
Generally it isn't considered art theft if somebody just shares the image in a "look at this cool thing" kind of way.

But then there are those that believe Google Images is a free market.
Everything on the simple yet powerful search engine that practically owns the internet itself MUST be free to use, right?
Wrong.
Anyone with a set of eyes and a tiny bit of awareness would know that's really not the case.
Type in any search term, open any image within the engine (you know, before going to the image source) and you see this written neatly nearby:

"Images may be subject to copyright."

Then why does Google have this image, then?
Well, you see, Google doesn't.
Google doesn't own a single one of the images you can find in the image search. It doesn't "have" any of them.
The Google Images search simply finds these images where they are and displays them on a grid for you to see. There is always the option to go to the website where the image displayed is from.

So when you're looking for art to use, regardless of its purpose, finding it on Google Images is not a free ticket!
You'll have to put some effort into actually asking the artist if you're allowed to use it.
That is, if asking the artist is even necessary.
Often an artist writes whether or not you're allowed to use their art on their front page. If that isn't there, check the image's Creative Commons licence, it'll tell you exactly if you're allowed to use it and how. If neither of those are present, its pretty safe to assume that, no, the artist doesn't like others using their art.

Whether you're allowed to use an image, or if you found a piece of art and you can't find out who it belongs to (which is kinda difficult not to. I mean, just use Google's linked/uploaded image search) then its always, and I mean ALWAYS still necessary to say that you don't own the art.
Yes, no matter how you edit said art piece, the only things that are yours are the edits and never the art itself.
Plenty of people I've seen saying that a certain thing is theirs simply because they switched the colours or added a misshapen blotch in MS Paint.
Tracing doesn't make it yours either. You're literally just running over lines that have already been made. Nothing original there.
These delusion that should just die.

There are ways of finding images that are completely 100% royalty free.
Free to use in any way or form you want. And one of the best ones is this:
search.creativecommons.org/

The creative commons search engine.
You can tweak what kind of commons you want to search for and on what its sources are based on, but you are sure that every single image you find with this has a free to use licence, some of them even for commercial uses.

I hope this helps for anyone who usually runs into problems being accused of art theft.