{"id":13390,"date":"2025-10-18T16:01:57","date_gmt":"2025-10-18T07:01:57","guid":{"rendered":"https:\/\/m365jp.net\/?p=13390"},"modified":"2025-10-18T16:03:42","modified_gmt":"2025-10-18T07:03:42","slug":"mc1174855-update-to-inline-image-representation-in-outlook-on-the-web-and-new-outlook-for-windows","status":"publish","type":"post","link":"https:\/\/m365jp.net\/index.php\/2025-10-18-mc1174855-update-to-inline-image-representation-in-outlook-on-the-web-and-new-outlook-for-windows","title":{"rendered":"MC1174855 | Update to inline image representation in Outlook on the web and new Outlook for Windows"},"content":{"rendered":"
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MC1174855 | Update to inline image representation in Outlook on the web and new Outlook for Windows<\/th>\n<\/tr>\n<\/tbody>\n<\/table>\n
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Classification<\/th>\nplanForChange<\/td>\n<\/tr>\n
Last Updated<\/th>\n10\/18\/2025 06:41:00<\/td>\n<\/tr>\n
Start Time<\/th>\n10\/18\/2025 06:40:35<\/td>\n<\/tr>\n
End Time<\/th>\n01\/15\/2026 08:00:00<\/td>\n<\/tr>\n
Action Required By Date<\/th>\n2025-11-15T08:00:00Z<\/td>\n<\/tr>\n
Message Content<\/th>\n\n

[Introduction]<\/b><\/p>\n

<\/p>\n

Starting November 15, 2025, Outlook on the web and the new Outlook for Windows will begin rolling out an update to how inline images are represented in the HTML body of emails. This change is part of Microsoft\u2019s ongoing security improvements and will affect how Outlook add-ins identify and process inline images using the attachment ID. Specifically, the update transitions from using tokenized image URLs to a more secure method using content IDs and request headers.<\/p>\n

[When this will happen:]<\/b><\/p>\n

<\/p>\n

This change will begin rolling out on November 15, 2025, to Production users. Rollouts to other environments will begin after Production rollouts are 100% complete.<\/p>\n

[How this affects your organization:]<\/b><\/p>\n

What’s changing:<\/b><\/p>\n

Previously, inline images in the HTML mail body were represented with a URL containing the attachment ID as a query parameter. Developers could parse the HTML and do one of the following.<\/p>\n