Friends; this concerns a problem which afflicts a lot of people, systems, mail providers, OS's, mail clients/apps.
User gets a message in the inbox - a legitimate one from a friend. in the message we find , a layer or three deep, the REAL original message from someone three forwards back, and in that message are images - jpg's or other.
the images, despite being nested somewhat deep, look fine! voila! the make it through the labyrinth to the users email application and display. The user likes it so much he forwards to you or me.
We receive it, and the images will NOT display - not in Gmail, not in Thunderbird, not in Outlook, not in IE11, not in Firefox. There seems to be an image there, but visible is just the frame.

Firefox has had more trouble, it seems, than other ways of accessing such - their rendering bails if the image tags are nested too deeply - there's some sort of threshold that gets breached and the tag is not dealt with. That's sorta forgivable, but what I'm seeing is more pervasive as noted above.

is there a cure or is it too mysterious? Are there any ISP's or mail contractors that are, unbeknown to the user, stripping something vital from an otherwise intact forwarded mail?