Yeah, I have that problem too, only reverse. I am a Unix admin. I get screenshots pasted directly into Outlook that come to me as "OLE_embedded" in Thunderbird. Just attach a
.jpg, don't embed it and just assume that someone else is using your same client to read your email.
OTOH, I can reasonably assume that if they really wanted help they would have sent it in a readable format in the first place.