OK, so you are baffled that you got here and want to know what's up. Understandable!
This site uses https://pnut.io to host pictures and organize them in "channels". Pnut is a small social network. It requires an invite or a subscription to join... You can get one of those on their site.
Once you have an account, come on back here and log into this app.
The Pnut Gallery is still very early in development. Currently you have to use any other Pnut app to upload files. Soon, it will be able to handle everything itself.
Authorize Pnut.gallery on Pnut