Every platform has strengths and weaknesses, but tumblr is 2 things that make it (in my opinion) the best site for artwork as a whole: 1: It’s image-centric. While it does video, text, and audio, the easiest thing to see and post are images (well, and gifs but I still have no idea how to make those which is both embarrassing and makes me feel very old) and 2: It’s extremely interconnected in how things are shared from the basic reblogging, liking, and following, to deeper connections through tags, fandoms, art submission and curation tumblrs like eatsleepdraw or supersonic, it’s not exclusive to just art like deviant art (so there’s more people to expose it to), and also unlike say: Facebook, there’s no algorithm that hides your work from a large portion of your followers unless you sponsor a post.
It’s not a flawless platform — it has some pretty hostile sub-cultures, rampant unchecked misinformation (watch out for processed chicken nuggets and Onion headlines taken out of context), and maybe ever so slightly too much idolizing of certain male actors in their late 30s and early 40s — but as a whole when it comes to sharing art, I think it’s pretty great — it’s where I see most of the art I enjoy.
A few artists or curation sites worth checking out here: alicexz, Owen Freeman, Sterling Hundley, Frogman, Fer1972, SuperSonicElectronic, Euclase, David Kassan, and a shit ton more, but those come to mind immediately.
Useful information- Sam’s Spratt Opinion on using Tumblr as a place to showcase your work