i spend far too much time taking screenshots and creating mockups in glade and
it would be a huge help if Glade had something like  
"File, Export..."
which would pop a Save As... Dialog and allow to save as PNG/JPEG or any other
gdkpixbuf supported image format (but PNG is the most important format for me).  

It is a pain to have to open a whole other great big program just to take a
screenshot of the current window, so I hope you can see how useful a feature
like this could be.  

If you also provided a way to access this functionalty from the command line it
could also be very useful for projects that want to generate up to date
screenshots of their software on a regularly basis for their documentation or
website (and do so in an automatic way, integrated with their build system).  

I hope I have explained clearly enough but I think this feature could save me
huge amounts of time and make my use of glade much more efficient and enjoyable.