What would a legitimate vote look like? Are they supposed to circle the black mark to the left or what?
The black series of marks are edge borders, guides for the machines. If you look closely you can see ovals beside the candidate names. None are darkened. This was not a real vote. Some worker, I suspect, added the stray mark to the edge of the ballot. If they didn't, if a voter actually made that mark, there's no fair way to determine intent, and the ballot should be discarded. It's too odd that there are no marked ovals anywhere on the page, and wouldn't someone so confused as to what to do end up circling the name? Further, should someone so confused be considered capable of voting?
You can see the empty circles -- look close, in the photo, they look like tiny round watermarks.