Idea: Shrunk imeages in existing emails

[zimcad]

First, thanks a lot for this fork!

Customers often send emails with very big images to me, that i dont need in this resolution. Is there a chance to implement a way to reduce those images in an existing email manually?

[Betterbird]

Drive-by comment: The add-on is for composition, it manipulates images embedded or attached to messages being composed.

Images in received mails sit in some multipart/mixed, multipart/related or sometimes erroneously multipart/alternative MIME part of the message. Since TB has no API to replace message parts, the add-on would have to replace the entire message (while deleting the existing one) and replace that MIME part in the meantime.

There are add-ons which do this sort of thing, like "Header Tools Lite" or "Header Tools Improved" which replace messages after having changed message headers or the content of a body part.

[memeller]

@Betterbird is right - there is no API that would allow message body modification. I think that the reason for this is quite simple - the content of emails should not be modified on the server, other than adding headers / changing the subject to e.g. mark them as spam.
However, it is possible to achieve the desired effect of manipulating email content by using some tricks. There is a great extension called EditEmailSubject-MX that enables you to edit the subject. The author has come up with a clever way to add a new email to the same folder as the original, but with modified content. Using his method and my quickly written (and probably not always working) parser, I was able to get a poc for this feature.

• There is no right-click menu in this version (as there is no context script to add such functionality), but there should be a notification displayed for messages with images (attached/inline that meet the size criteria).
• If you choose to resize the images, you should get a copy of your email with resized images next to your original email.
• For inline images the image is resized, but the width and height of the image element in body is not changed. This results in small image being stretched to the size of original image.

Unfortunately, I cannot guarantee that my parser will work for all emails. There is a chance that an email may become corrupted / lost due to an incompatibility between my parser and the email client from which the email originated. So I am not sure if such a feature should be added to the main release. Perhaps if I added some warnings at various stages of the resizing process and always kept a copy of the original email locally (as EditEmailSubject-MX does)?
Testing
Since xpi files are not supported here, please change the extension from .zip to .xpi after downloading. The extension has a different id and name, so that it can be installed along the main release.
shrunked v5.8 alpha.zip