So, you want to be able to change the details for one or many files in one go - I would suggest a file view that lists all the files with a panel to one side that lists the details of the selected file or files as input boxes - the user could select a single file and edit its details in the side panel or they could select multiple files and edit their details in the side panel as though they were one file - For example: the user selects a single file, clicks into the 'name' input and changes the 'name' of that file. The user selects 3 or 4 files and clicks into the 'style' input and changes the 'style' value for all selected files.
I'm sure I've seen this kind of interaction somewhere (to do with MP3 player software) but I can't think where!
It looks something like this (very simplified sketch)
