Some Squadrons that support the community have Decals. And Decals for events.
Fuel Rats, Canonn Institute, Distant Worlds 1 and 2...
Livery are cosmetic items for Ships, Ship-Launched Fighters, and SRVs. Livery items can be purchased with ARX from the in-game Elite Dangerous Store. These are added or removed via the Livery menu in the game's main menu or at any Station with Outfitting services. Available Livery items include...
elite-dangerous.fandom.com
Make a Squadron, that support a webpage like
www.fuelrats.com or canonn.science, and you will have your own Decal approved by FDev (anything not offensive)
Outside this, Decals are a livery that cost Arx (but one of the cheap items), uploading your own decals remove some benefit from FDev. At least the option for Activating Custom Decals need to cost some ARX.
I want a discount in Paintjob/Suit based in Squadron colors. Im a Canonn member, with my own Decal, but I need to purchase Orange Livery for the ship I want to use in Canonn Activities.