If you are not a part of WhoLock fandom this won't matter or make sense to you.
Ok so in the picture John and Sherlock are standing in an alleyway, or something and on the wall it says Bad Wolf and in the water on the ground there is a reflection of the TARDIS in the water. MYCROFT YOU'RE SLACKING YOU MUST KEEP THE DOCTOR AND SHERLOCK APART OR THE UNIVERSE WOULD EXPLODE.