Hi @Bon Macalindong ,
I would first recommend ensuring that your image isn't too large. The thumbnailPhoto attribute can store a user photo as large as 100 kilobytes. Exchange Online accepts only a photo that's no larger than 10 KB from Entra ID/Azure AD. To be on the safe side, you can shrink the photo to 1080p wide and 72ppi.
I have also seen a few users report this issue due to accessibility settings in Outlook conflicting with the image rendering, so I would double-check these settings too. You can try temporarily disabling accessibility features to troubleshoot this. https://support.microsoft.com/en-us/office/make-your-outlook-email-accessible-to-people-with-disabilities-71ce71f4-7b15-4b7a-a2e3-cf91721bbacb
I would recommend testing by opening the mail in the Edge browser and ensuring that attachments are allowed under Settings > Mail > Layout.
Otherwise the inviter’s name and profile image should be included if they have one set up in Azure.
https://learn.microsoft.com/en-us/entra/external-id/invitation-email-elements
Let me know if this helps and if you still face this issue in all scenarios.
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