One of the biggest limitations of inserting images in the signatures as illustrated above is that the image is attached as a file. How to insert HTML email signature in Office 365?

Some of the email clients may convert embedded images as attachments.

This may cause emails to get rejected due to the size limits.

Since you are directly embedding the image into your signature, there will be a direct increase in the size of the email.

Some of the email clients may reject and email may be blocked by anti-virus software.

You can view it when the email client is offline.

Images will be displayed automatically when the email is viewed.

If the linked URL is not accessible or it is deleted / renamed then signature image display may be affected.

The recipient has to be online to view the images as images are directly viewed from the linked URL.

Images may not be displayed automatically in some of the email clients (recipient must click a ‘download images’ button or change settings for the specific sender).

Hence there is the possibility of email getting rejected or blocked by email clients due to the size limit.

This is a great advantage in the successful delivery of the email with the linked images.

Cannot be blocked by anti-virus software.

What are the pros and cons of embedded and linked images? Linked Images PROS

Add image to email signature outlook