When you are signed in as the owner of a dotphoto account, you see ALL your photos and you do not see the watermarks on your thumbnails because, of course, you are the owner of the account. Because browsers track your activity, you must follow a different path to see what your guests see. Here's how:

Sign out of your dotphoto account, open a private browsing window, and sign in as a guest.

Sign out of your dotphoto account

Open a private browsing window.

Choose Incognito window in Chrome or InPrivate window in Microsoft Edge

Sign in with your Guest credentials. Use your account's guest password if you set one up. To see a specific album, use the password for that album.