automatically resizing images...

[Batfastad]

I plan to have a container field in a database which will store images.

The user uploads the image, and the actual image is stored in the field. Not just a reference.

Is it possible (with plugins or native filemaker functions) to have another field, that automatically resizes the image to say, 150px wide - and keeps a copy of it in there?

I'm asking as I want to be able to get at these images from the web using CDML, but obviously I don't want a 2MB jpeg to be downloaded by the client every time they visit a particular page. I'd like just to be able to pull the contents of another field in, with the image automatically resized.

Any ideas?

Thanks in advance.