The Help page makes it really simple:
To upload photos:
Click Add Photo/Video at the top of your homepage.
Pick Create Photo Album.
Pick the image files you want to upload.
Where I and a lot folks get stuck is selecting multiple photos to upload - you would think holding the shift key and arrowing down or mouse-clicking each image would make a selection - like it does in most programs, especially Windows. But no. Shift-select appears to work but does nothing when you hit the OK button - it just goes back to the main page.
To pick multiple photos at once, hold down the Control button on your PC, or the Command button on your Mac, while clicking the image files.
Only with Control-select does the code for the uploader kick in and run. Don't ask me why.
While your files are uploading:
- Add an album title and description
- Use the audience selector to choose who can see the album (Note: If you tag people, their friends will be able to see the pictures they’re tagged in)
- Add captions, tags, and locations to photos as each one finishes uploading
- Check the progress bar to see the estimated remaining time for your album upload. Once it's complete, click Post Photos.
Be aware the initial privacy settings appear to stick - post as public and it stays that way - there's no obvious way to change album visibility except to go through and hide photos individually. RC