Positioning the voting buttons such that they will always be in the same place is a very sensible idea. But you would be incorrect to assume the thumbnail photo is always the same height. In fact, it is not always the same height and therefore placing the voting buttons beneath the photo may not be the best solution.
The height of the thumbnail photo actually varies and sometimes it does
Right but it never goes below the summary text, so with the current design, that space is free.