How do I accept the invitation to be a Contributor?

When you receive an auto-generated email from Image Finder with the Subject Line: 'Figure list invite - [Figures List Name]' you are invited to contribute. Click the 'Click here' link in the body of the invite to either register for an account or to log in to Image Finder. See How do I register with Image Finder? and How do I log in to or out of Image Finder?

You need to accept the invitation to be able to contribute to that Figures List.