[JENKINS-75800] Allow email attachments to have inline content-disposition

[jenkins-infra-bot]

Emails that have an `` at the top, also show the attachment in the email. This becomes a problem when emailed to a Microsoft Teams channel. The image appears inside the message, but also as an attachment preview under it.

I believe the root cause is that the attachment does not have the necessary "Content-Disposition" header set to "inline".

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Originally reported by axieum, imported from: Allow email attachments to have inline content-disposition

• status: Open
• priority: Minor
• component(s): email-ext-plugin
• resolution: Unresolved
• votes: 0
• watchers: 3
• imported: 20251211-193728

Raw content of original issue

Emails that have an `<img src="cid:banner.png">` at the top, also show the attachment in the email. This becomes a problem when emailed to a Microsoft Teams channel. The image appears inside the message, but also as an attachment preview under it.

I believe the root cause is that the attachment does not have the necessary "Content-Disposition" header set to "inline".