Is there a reason why we can't attach pics to private messages?

 

Just store the picture somewhere (plenty of hosting possibilities) and provide a link.
If I'd own the forum, I wouldn't want to allow that feature either. People might abuse it, sending a lot of large pictures - and then the forum server needed a lot of disc space to host them.

 

I just host them on Imageshack and then use the [IMG]...[/IMG] tags.

 

I know I can host them elsewhere if necessary. Just wanted to know why it's not allowed.

 

would take up too much room maybe?

 

I'd guess Tamas has the right of it. I'll see if I can find out what the rational is for you.