This sounds like a good idea, however I personally think that all staff should be able to post images of the most used exploits.

I find an issue with this that it will block the whole chat with one picture if you ever wanted to see what others have written and so you will have to scroll to get the information. Another issue that I find with this is that I have never seen anyone use this on Gmod, so I am not sure if it's possible to even implement it.

By the way how big are the pictures supposed to be so that it would be possible to look at them without "spamming" the chat?