Can images or HTML code trigger spam filters?

Yes, certain image and HTML patterns can trigger spam filters. Image-heavy emails with minimal text are particularly suspicious because spammers use them to hide content from text-based analysis.

Filters evaluate text-to-image ratio. An email that is essentially one large image with no readable text raises immediate flags. This pattern suggests the sender is trying to evade content scanning.

Poor HTML practices also trigger rules. Broken tags, invisible text (white text on white background), tiny fonts, and hidden elements are all spam techniques that filters detect.

Clean, well-structured HTML with a healthy balance of text and images passes filters more easily. Always include a plain text alternative, which both improves deliverability and serves users who prefer it.

Transparent cargo passes inspection smoothly. Attempts to hide content invite thorough examination.