Attachments: Up to 2 attachments (including images) can be used with a maximum of 512.0 KiB each and 1.0 MiB total.
The JET Quotes Plugin will request a snapshot and then continue streaming the real time data. If you just want to get a snapshot you can stop the subscription manually. Another option is to keep the subscription running and cache it until needed.
Retrieving market data at a snap time
What is the maximum number is RICs you can request real-time (quotes) data for?
Looping through single data requests
Question about Auth Service to App Studio Team