Ok creating a plugin that given a specific command puts an image directly into the conversation. Only i want the whole image (size constrained) not a thumbnail. Is there any way to do this? Had a quick search around but couldnt bring anything up on this.

It's not going to be easy, but Active Accessibility may help you out.

Ok ill be honest and claim ignorance on that one. Lots of stuff on google to wade through it appears. Is this something i can interface with easily enough or have you got an references to pages talking about using active accessibility objects with msn?

I haven't come across any examples using Messenger, but the examples that use other programs are equally valid for Messenger. You'll need a utility called 'Accessibility Explorer' to find the structure of the convo window