How to add images in reviews?

Does anyone know if it is possible to add images in reviews? I can't see the "Add Image" button when writing a review.

actually you can, but you have to copy paste it into the review.
However i agree with you that a proper way to add images is missing.
Also by doing copy paste you are hot linking when the image is not from this site, so try and only copy paste images that are on giant bomb's server.

Even when I try to copy and paste it doesn't work, any ideas? 

I think at the moment it is intended that you do not include images, although I would support implementing the WYSIWYG editor for them. Would be a very cool feature.