Images in email signatures – linked or embedded?
The HTML format makes it possible to add images to emails and email signatures. Graphics can be included as:
- linked (hosted) images - online graphical resources are referenced in the email's HTML source by using a URL: <IMG src="https://www.codetwo.com/images/image.jpg">
- embedded images - local graphics are added to emails as hidden attachments (referenced in the email's source via a Content-ID: <IMG src="cid:unique-content-id">).
In the table below you can learn about the advantages and disadvantages of each method.
Linked/hosted images
Downloaded directly from server |
Embedded images
Included in every message |
| Advantages |
- The email size is not increased by images - they are downloaded from a web source when an email is viewed
- Emails with linked images are rarely blocked by antivirus software
- You can track who received your email by analyzing web traffic for the images you linked in this message. Learn more
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- Images are displayed automatically when a message is viewed
- Recipients are never asked by their email client to download images
- Images are not affected by external factors (e.g. accidental deleting, image URL changes, image server accessibility, etc.)
- Embedded images are visible when an email client works in offline mode
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| Disadvantages |
- In most email clients, images are not visible until the recipient agrees to download them into the client
- A server to host your graphics files is required
- Image availability in email depends on external factors, such as accessibility of the image hosting server
- Some filters may recognize your messages as SPAM
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- Embedded images increase the message size
- Emails can sometimes be blocked by antivirus software
- Embedded images are sometimes removed by mobile devices*
* Our software can automatically fix this issue for iPhones and iPads. Learn more
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