If you are seeing this then go to the View menu and uncheck Display Attachments Inline.

If you're recipients are seeing it and using Thunderbird tell them to do the same. If they are using a different email client, tell them to learn how to work their software and turn it off.

Thanks Airmail for the reply but there should be a way to solve this without putting the burden on everyone who receives an email from me. Seems that the email sender (ie me) should be able to fix this somehow in TB when I send the email.

How do you figure it is a burden. Thunderbird is attaching the image or file like you asked it to. It has the option to display that attachment inline if desired. This does not mean the file is inserted. It means you turned on an option to display attachments. You nor Thunderbird has any control how anyone else has their software set to work. Maybe you should learn the difference between inserting an image and attaching one. They are two completely different operations. If you are inserting the image then you are the problem. If you attach the image and the recipient has the option to display those attachments inline turned on they are the problem and try as you might you cannot fix that.

If anyone has any suggestion or any advice on the safety of changing the config-editor (Tools - Options - Advanced - Config Editor) to change the mail.content_disposition_type instruction by setting preferences to '1'. , I'd really appreciate hearing from you. Thanks.

What Airmail said. +1.

Thunderbird can display some attachments, as can many other email clients. Whether or not it does is at the behest of its user, and it is indifferent to the wishes or intentions of the sender. Whatever that config switch does cannot change the basic facts of how email clients work.

Hmmm...

http://kb.mozillazine.org/Send_attachments_as_real_attachments

I'd like to see some justification for the claim there that there is more than one way to send attachments. All attachments are sent inline. I wonder what a "real attachment" is.

Aren't only Attachments of image files sent inline?

When I send a PDF file as an Attachment, the content does not show inline in the body of the email I receive (even if I click on 'view/display attachments inline') -- it only comes as an Attachment (listed at the bottom of the email, that I need to click on and open to see the contents).

You are confusing the transmission method (which is what Zeno is talking about) and display.

All attachments are transferred as mime encoded text streams in the body of the email, regardless of their content. ipso faco "inline". Images for instance will be either "inline" or "remote"

From the user perspective there is inline as an image embedded in the text, just as the names on the left in this forum have images associated with them. HTML folk often refer to those as "inline" as well. but that is display inline.

I am sure you receive marketing email which are basically a big collection of images, we all get some of them. Want them or not. But there is an add-on for Thunderbird that forces all the images in those email to appear as an attachment.

See https://addons.mozilla.org/en-US/thunderbird/addon/show-all-body-parts/

That add-on makes attachments magically appear, because it ignores a flag on the attachment that says "inline" which Thunderbird normally respects. Just as the display images inline menu item allows the user to choose to display attachments or not. The option is offered as a convenience. why should you have to open a JPG or TXT file to see the content when Thunderbird knows what to do with them. A convenience I appreciate

It is just unfortunate in my eyes that we can not greatly expand the list of inline attachments that are displayed, but it is just not really an option. Although we may see it happen with PDF, as Mozilla are working on a JavaScript PDF viewer than might one day be included in Thunderbird if it becomes stable and fast enough..

Thanks Matt. I don't understand the technical info but I guess I get the gist. I'm used to my old email system which functioned differently, and I think I have been confusing the transmission method with the display. I've been doing some more testing on sending images and it does seem (as you say) that the images I've sent as Attachments don't necessarily show up in the body of the recipient's email (eg, in outlook for ex). So thanks all for helping me to realize that.

I don't necessarily mind the recipient seeing the image in the body of his email, but usually when I send an image file attachment it's for professional reasons and it's important that the image be seen at its best quality, which doesn't happen when the first view of it is in the email body. Especially in TB where it seems that the image in the email body is so very very large it's awkward to see well. (Which seems different than in hotmail or outlook, which I hate to use as models of anything!) I haven't found a way to control that without also changing the size and quality of the image file I'm attaching. So I guess I'll still have a problem with recipients who use TB and haven't turned off the 'display attachments inline' option, hopefully a small group.

Thanks again to all for the help.