Since it appears that FA has put the ability to upload images bigger than 1280x1280 behind a paywall now, I'd like to point you to my account on Weasyl which doesn't have the size limits or a paywall.
https://www.weasyl.com/~captainkaboom

Recently one of my favourite characters, Raoul by Mowsky went up for auction with all of his art, and I managed to nab him at a pretty steep price, so I'm not gonna file any new comms for a bit and I may start uploading his art to my account as Mowsky's gonna wipe all his accounts.

Welcome Raoul to my crew with Alfred and Roland, I figure they'll get along nicely

I have commissioned some lewd stuff with my characters and I've kept from publicly uploading them for while since I'm pretty shy and I was a little scared of possible unwanted attention, however I've been reconsidering and have started to get over this fear, so you may see some saucy stuff of Alfred and Roland soon

On FA you can easily circumvent the 1280x1280p image size limit by just uploading your image normally, then going to 'update source file' under the submission options then select the same image again and re-upload, when it's done the post image will be in its full original size!
I've done it with all my posts and it can be done on older uploads to.