Email Signature Images Showing as Attachments

A common signature complaint is that every email arrives with small attachments named image001.png or similar, or that recipients see a paperclip icon on messages that have no real attachment. The cause is almost always embedded images. When a signature's logo or icons are pasted in or inserted from a local file, many clients, particularly Outlook on Windows, embed the image in the message as a CID attachment and reference it from the HTML. Some receiving clients display those inline, while others, especially on mobile or after forwarding, list them as attachments. The same thing happens when a signature is copied between programs and the image travels as file data rather than a link. The fix is to use hosted images: upload the logo and icons to a web server and reference them by an absolute https URL in the signature HTML, so the image is fetched when the email is opened and nothing is attached. Hosted images also keep each message lighter. The trade-off is that hosted images are hidden until recipients allow images in some clients, so every image needs alt text and the essential details must be live text.