After clicking the gallery button on the navigation bar, you'll be taken to this page:
Click on the '+' buttons to submit to the gallery! It's required you submit gallery links rather than Discord/Toyhou.se/etc. hotlinks for prompts! Any submissions with non on-site gallery links will be denied. Gallery submissions can still be linked to before official approval/while pending, so there should be no reason you can't link it when submitting a piece to be redeemed!
KEEP IN MIND THAT SOMETIMES OUTSIDE FORMATTING WILL NOT ALLOW YOU TO UPLOAD YOUR SUBMISSION ON SITE OCASSIONALLY, IF THIS HAPPENS YOURE ALLOWED TO LINK A GOOGLE DOC IN THE TEXT SECTION BUT IT STILL NEEDS TO BE SUBMITTED ON SITE!
Fill out the basic info as needed, and click submit!