User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:51.0) Gecko/20100101 Firefox/51.0 Build ID: 20170125094131 Steps to reproduce: Tried to compose a message using a template with a picture background. (I use the Stationeyr add-on) Actual results: The template's background picture did not load. I then changed the configuration "mail.compose.attach_http_images" to "true" and still nothing happened. Expected results: Should have been able to compose a message using a template with a picture background.
Since version 52 TB will no longer show images in compositions that are referenced from files (<img src="file:// ...">. See bug 1322155. We have notified add-on authors to adapt their add-ons. Please contact the add-on author, CC'ed here (Arivald).
Arivald, you need to copy this code to insert the content of files as data URI: https://dxr.mozilla.org/comm-central/rev/fdc6a3e536479536fffdfd057d41e65aa191d871/mail/components/compose/content/MsgComposeCommands.js#5640