On Windows, Thunderbird 3.1.11 is unable to display images attached to messages inline, despite having checked View->DisplayAttachmentsInline Instead I have to right-click open, and then it starts the very slow "PaintShop Pro Photo X2 Image" application. On Linux, and on older versions for Windows, attached images could be displayed directly.

After further testing, it appears that this doesn't happen with all image attachments, but only if they are nested within a multipart/related and or multipart/alternative

This looks like bug 659242 ?

To me, bug 659242 looks more like a failure to display the message at all if it has a certain structure. What I am referring here in this bug (692040) is just a failure to display images

To Alain Knaff(bug opener): Could you please attach(never paste) mail data which consistently reproduces your problem? - Save mail as .eml file, then attach the .eml file to this bug. Remove or replace sensitive data, such as email address which is irrelevant to problem, before attach to this bug, please.

Here is a message showing the issue. It's supposed to contain a picture... but the picture is not shown :-(

> MSG: Content-type: multipart/related REL1: Content-type: multipart/alternative > ALT1: Content-type: text/plain > ALT2: Content-type text/html > REL2: Content-type image/gif Image file is in multipart/related, > --=_related 0033CFCAC1257935_= > Content-Type: image/jpeg > Content-ID: <_2_097568980975662C0033CFC9C1257935> and is correctly pointed by text/html(quoted-printable) under multipart/alternative under the multipart/related. > <img src=3Dcid:=5F2=5F097568980975662C0033CFC9C1257935 Do you set View/Message Body As/Original HTML or Simple HTML? If image/jpeg is not shown by Tb even if HTML mode display, new Tb bug. If View/Message Body As/Plain Text, Tb uses text/plain part under multipart/alternative and ignores text/html part based on definition of multipart/alternative. And, image/jpeg part under multipart/related is not used at any place, because text/plain part is used as message body and because it's a part in multipart/related. If you are requesting "display of the image/jpeg part as attachment when View/Message Body As/Plain Text, even though image/jpeg is placed in multipart/related", dup of bug 602718. If you are requesting "inline display of the image/jpeg without attachment icon when View/Message Body As/Plain Text and View/Display Attachments in Inline, even though image/jpeg is placed in multipart/related", it's probably not fulfiled by bug 602718. If so, it's perhaps new enhancement request.

Last request may be a dup of Bug 674473 or fulfiled by fix for that bug, although that bug is for not-referred/not-inline-displayable part under multipart/related.