I first clicked on Users Photos, then on view All Photos of the Day. The next screen, just below the top PhotoRardar heading and the top advertisments, there was a box with "Search Within Photos" on the left, a white box to the right, and then a dark gray box saying Search.
I typed in some keywords that I had attached to a photo one at a time into the white area. Two of the three words I had used for my photos came up with the message that no images were found.
The third tag that I put into the white box came up with a Camera Review link, and a Blog link, but not photograph links.
Since the title for the search was titled "Search Within Photos" then only photographs that included that word as a tag should be the only ones to be returned by that search.