MD trades require goodwill and trust on both sides. When that trust comes into question, it is a best practice to wait until the trade in question is over before complaining, because calling BS on someone after a trade occurs leads to much stricter consequences, and a loose trade embargo will follow naturally from any accusation, true or false, and this is a good thing.
Obviously such an image or set of images should include server time to verify that bids were placed between your bids.