When I create a JPG as signature, sending message from Conversation View generate an SMTP error.
The message is sending normally using the standard interface with the jpg at the bottom.
It's the same with a text signature in fact.
I use T15.0.1 and conversations 2.4.3
L'envoi du message a échoué.
Le message n'a pas pu être envoyé car la connexion au serveur SMTP "ns0.ovh.net" a expiré.
Essayez à nouveau ou contactez votre administrateur réseau
I don't think it's related to the signature. More likely, the quick reply is picking the wrong identity for replying. Have you checked all your identities and smtp servers?
Do you have several identities?
Please check which email address the quick reply is picking; then, please check each identity associated to that email adress. The quick reply may be picking a different identity than the regular compose window.
Somehow the quick reply is picking your OVH server for sending the message.
the email interface for github doesn't allow you to attach pictures, so I'm not sure I can see what you're talking about
i'm having exactly the same problem when sending a quick reply with a .jpg signature:
"Sending of message failed. The message could not be sent because the connection to SMTP server smtp.gmail.com timed out. Try again or contact your network administrator."
Please try the latest version at http://jonathan.xulforum.org/files/gcv-nightlies/201406201054-html-reply.xpi and tell me if it fixes your issue (if it does, feel free to close this ticket!).