Cataloguing
 

I use a lot of illustrations in various articles and papers I write, and frequently also reuse some illustrations. I store references to my illustrations in Expression media (former iView Media), where I can assign what I need of metadata to the images, preview them, and drag-and-drog to new papers when I like. Expression media reads most kinds of graphic formats, including images inside Keynote-files. OmniGraffle-format is not supported, and I would like to know if there are any other solution to archiving and cataloguing illustrations made in Graffle?

Perhaps export as PDF?

Inconvenient
 

Of course I can export as pds (or almost any other format) but that is quite inconvenient when I have 10+++ canvases. The best would be if the different canvases were accessible from outside graffle in some way, like Keynote-graphics obviously are.