Embedded vs Hosted Images.
Many business use embedded images including logos in the signatures. They have one main advantage in that the images are always visible in the email when it is initially sent.
With hosted images, if the recipient has “Downloadable Images” turned off in their mail settings, they will be asked if they wish to view the images in the signature. This is not usually an issue on mobile phones where most people read their emails.
This one advantage comes with a high price. There are five key problems with embedded images that are not present with hosted images:
1. Images that are embedded are treated as attachments. Simply put, every email sent will display the paperclip icon whether or not there is an actual attachment. This is a well known frustration for most recipients who must spend their time looking for attachments that usually don’t exist.
2. Embedded images add to the file size of the email for both the sender and the recipient.
3. Because spam often includes embedded images, spam filters are much more likely to attribute a higher spam score to an email with an embedded image.
Missing on Replies
4. Embedded images in signatures are often stripped out from the email thread leaving only the file names when viewed on iOS devices such as an iPhone or iPad.
5. Embedded images can not be updated without creating a new signature. Hosted images can be updated remotely for any number of users all at the same time. This makes it ideal for featured promotions in the signature.