Okay, good.
It doesn't really say. The text is "the targets can communicate telepathically through the bond whether or not they have a common language"
I think, in telepathic folklore, images can be transmitted and books on "how to do telepathy" seem to suggest trying to project an image, possibly accompanied by words. For example,
http://www.wikihow.com/Develop-Telepathy
I did once take part in a real telepathy experiment and successfully received a verbal phrase accompanied by an image. The phrase was clear but the image was oddly small and far away and made no sense until afterwards. At the time, I mistook what the image represented. So in my experience, images are possible but unreliable.
I guess it's DM's call whether or not pictures are possible. If you rule not, the wizard can describe what he sees in a terse sentence or two, although he could do that in ordinary speech anyway without needing the bond. I was thinking that the bond ought to confer some benefit, but not as great as effectively granting truesight to everyone.
Tricky stuff, magic