Hello Clive Dlima- Mansley Serviced Apartments,
Thank you for posting on Microsoft Community.
I understand that you’re encountering an "email signature image size" where the same image used in the email signature works normally for most users, however for some users, whilst appearing normally at setup, when sending emails the image is extremely large.
To narrow down the issue you are facing, could you please provide the following information:
- Could you confirm which version of Outlook the users encountering the issue are using? What version of Outlook do I have? - Microsoft Support
- Are the users experiencing this issue using different DPI settings? Please check the display settings on their devices.
- Are all users composing and sending emails in HTML format?
- Can you confirm the format and size of the image used in the signature?
In the meantime, these guided steps may help you troubleshoot this issue:
1. Host the image on a publicly accessible server and use the absolute URL in your email signature. Note: To get a publicly accessible URL, you can upload your image to OneDrive and generate a sharing link. Here's how:
- Upload your image to OneDrive.
- Right-click the image and select "Generate a sharing link".
- Copy the link
2. Stick to widely supported formats like PNG, JPEG, or GIF. Avoid using BMP or TIFF.
3.: Resize the image to a suitable size (e.g., 100x100 pixels) to prevent scaling issues.
- Go to "Insert" > "Pictures" > "Online Pictures" and enter the image URL. This ensures the image is linked correctly.
- Avoid using CSS or HTML resizing, instead, resize the image itself to prevent inconsistent rendering.
- Test across the Outlook versions and devices of the users. Verify the image appears correctly in different Outlook versions.
We look forward to hearing from you; Please understand that our initial reply may not always immediately resolve the issue. However, with your help and more detailed information, we can work together to find a solution. Thank you for your cooperation.
Sincerely,
Eleni | Microsoft Community Moderator