First:
Checking with on text events and completely re-displaying how text is displayed into images is completely different. ON TEXT is looking for a matching event, but you're talking something completely different.
Now, where are we going with this pictures in text thing? You mean replace LOL with a cutesy little image that says "LOL!" AOL-like? Eh, yeaaaaaaaaaaaaaaah. Okay. So then it comes to the point where people start begging "OH OH NOW THAT MIRC SUPPORTS PICTURES IN TEXT, I WANT TO BE ABLE TO SEND THAT PICTURE TO OTHER PEOPLE!". Then we'll get back into this same debate with such people trying to explain to them that fundamentally this would NEVER work outside of a DCC. Of course, these are the same people who have no idea what the concept of how to use DCC anyways.
Not to burst your bubble, but there should be a level of uniformity between IRC clients and servers. If the server doesn't support pictures going through it, then the IRC client really doesn't need to display pictures in text.
Find me any other Windows-based IRC client that handles the text this way and get back to me on it.