Up to 2 attachments (including images) can be used with a maximum of 524.3 kB each and 1.0 MB total.
Alexa starts recording only after it recognizes the wake word. You cannot randomly record conversation.
1 Person is following this question.
Alexa Voice Services can control set-top box ?
How to get voice query to my app with Amazon Voice Service or Alexa
Input voice request recognizance by Alexa Simulator.
Alexa is going to Listening state triggering wake word "Alexa" from its own response.
Alexa storing voice recording as diary