Relative image URLs in email signatures
A relative image URL such as /images/logo.png depends on a web page’s base address. Once that HTML is copied into an email client, the original page context is no longer a dependable base for resolving the asset.
SigLint finds the exact path: each relative image occurrence gets a line/column location so you can replace the affected URL rather than hunting through the whole signature.
Recommended approach
Use an absolute HTTPS URL such as https://example.com/images/logo.png, or use the target mail client’s supported embedded-image installation workflow. Verify the final installed signature in the real client.
Why this rule is deterministic
The checker does not need to fetch the image or send your HTML anywhere. It identifies image src values that begin with a root-relative or dot-relative path. The recommendation is based on the loss of the original web-page base URL when HTML moves into an email context.