Andy (or anyone else well versed with ImageMagick and Thumbnails)

I'm trying to write my own code to simply grab ONE specific field (I've several upload fields y my LSQL DB) I want to specify just one field and thumnail the image .. I simply want to allow users to upload an image and convert it on the fly, I simply don't undestand how I'm supposed to do that... Should I input the stream into ImageMagick using a file handle or I need to wait till the image uploads to a temp directory and then convert it? anyone?