NFT's or (Non fungible Tokens) can be many things, but when it comes to art, just like selling an actual painting you can also sell the digital copy of this painting when you digitize or "mint" it on a cryptocurrency blockchain as an NFT.
This creates a permanent record of ownership of this digital painting on this blockchain, and can be transferred/traded among people just like they send bitcoin or other cryptocurrencies now.
A normal painting can be duplicated but still be told apart from the original at most occasions.
When it's an NFT, each one has a unique "policy ID" that can't be duplicated. So if the original art owner created only one copy of his painting and minted it on the blockchain, no one can ever copy it with the same policy ID.

There is obviously a cost in minting your art on the blockchain. On the Ethereum blockchain for example, you can pay anywhere around $160 in ETH to turn a single image/photo into an NFT. But there is basically a ton of competition so your art needs to be next level to catch the eyes of NFT collectors there. but some art sells for millions $ worth of ETH.

There are also cheaper ways to mint NFT's on a different Blockchain, Cardano, whose NFT community is currently booming. Minting NFT's on Cardano is cheaper but still in the very early stages of development. It could cost around 10ADA which is currently around $12 for a single NFT and there already exists some easy ways but for larger scale projects development skills are required.

I am part of Cardano since the very beginning (2017) and recently been right in the middle of many NFT projects, have many NFT collector friends, and working with 2 artists on 2 different NFT projects to launch on Cardano.

I am offering my service to kickstart your NFT journey for a share of the profits. Your job will only be to have the art collection preferably with a website but we can take care of that too. And i will pay for minting the assets. I will also market them in my channels and sell them to collectors.

But i am Lebanese and i know how a Lebanese thinks, so if this encourages you to take the NFT leap and do it yourself, this makes me also happy. Cryptocurrency is freedom, especially for us Lebanese and we desperately need it!

DM's are open. If interested we can talk more :)