You are running into a glitch in the way Photos is handled in File Upload in Safari in Ventura. It used to show all your albums, but in Ventura, Safari and other browsers show only the full Library. It may really be something that Facebook and such companies have to revise in their web sites to take advantage of changes in the mac OS.
So you have to work around it for now. The search box is available, so you can try searching for your picture with its file name, a keyword you've assigned, a person, or a title. It helps to add keywords or titles to pictures as you go so you can find them later.
You can, before the upload, select your pictures in Photos, and then add a keyword, maybe Facebook033023 or something, to the info window (command-I) all at once. Then the search should give you all the pictures.
Another option is to export the pictures you're going to use to a folder, perhaps on you desktop. Then you can upload from there.
Also, you can leave feedback here:
Feedback - Photos - Apple
You might also leave feedback at Facebook.