Yes if the customer can create a custom application after analyzing the data pattern and loading that as a signature in the custom app and block it as needed.
I have seen in file blocking profile that I do not find a file type exif. But if this can be caught as a signature then yes we can have control over it.
I would suggest to post the question in dev center community.
It is"the online community for customers, partners, and employees to share custom content including Custom App-IDs, Custom Threats, Custom Reports, XML API integration, CLI scripts, and other tools. Use the discussion threads to ask questions and receive help from other members. The current samples would be a good start. "
There might be someone already who has worked on this app. Also you can submit a request for new app. The following link explains on how you can do that
Hope this helps.
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