Rob Nagel ,
the order of the events are :
client side select multiple files
client show file1 uploading
server fire FileValidating event
client show file1 finish
client show file2 uploading
server fire FileValidating event
client show file2 finish
...
client side fire Postback event
server side fire FileUploaded event for each file
server side fire UploadCompleted event
If you move/delete the temp file in FileValiding event, the FileUploaded of that file will not fire.
So you can resize the image , but please keep the filepath , and then move it in FileUploaded event.
Regards,
Terry