Why Your Email Signature Images Are Broken (Every Cause, Fixed)
A broken logo makes a signature worse than no signature. There are exactly seven common ways signature images break — work through them in order and you'll find yours.
Step by step
The image was attached, not embedded
Dragging a picture into Apple Mail's signature box sends it as an attachment — recipients get a paperclip file or an inline blob that breaks on reply. Fix: use an HTML signature whose image is a hosted web URL, not a file.
The image points at your own computer
A file://… path renders for you and literally nobody else. Fix: upload the image to public hosting and reference the https:// URL. (Autograph hosts your photo/logo automatically.)
iOS rewrote your pasted image
Pasting a signature copied from a received email into iPhone Settings converts images to internal webkit-fake-url:// references that resolve nowhere. Fix: copy clean HTML with hosted images instead — full walkthrough in our iPhone guide.
The recipient blocks remote images
Many clients (and Apple's Mail Privacy Protection) hide remote images until the reader allows them. You can't override this. Mitigation: meaningful alt text, and a signature that still reads well as text — good templates degrade gracefully.
Google Drive / OneDrive permissions
Gmail signatures built on a Drive image break the moment the file isn't public. Fix: host the image somewhere permission-free and immutable.
Outlook scaled it into blur
Outlook's Word engine resizes images by DPI; oversized sources come out fuzzy, tiny ones pixelated. Fix: serve the image at the exact display size (or a clean 2× retina version sized down in the HTML).
The image URL died
The generator you used shut down, or someone “cleaned up” the folder — every old email now shows a broken box. Fix: host signature images at immutable, permanent URLs (Autograph's hosting never rewrites an existing image).
Or never think about image hosting again
Autograph crops, bakes, and hosts your photo and logo at immutable URLs, builds Outlook-safe HTML, and installs it into Apple Mail in one click — images that render, everywhere, forever.
Download Autograph free See the templatesCommon questions
Why does my signature image show a question mark on iPhone?
Either it's a dead internal reference from pasting image data (cause 3), or iPhone simply doesn't load remote images in the signature preview — if a test email shows the image to recipients, it's fine.
Should I embed the image (base64) instead of hosting it?
Tempting, but no: several clients (notably Gmail) strip or block base64 images in signatures, and they bloat every message. Hosted https images are the approach that works across clients.
What image format is safest?
PNG for logos and graphics, JPEG for photos. Skip WebP/AVIF/BMP in signatures — client support is inconsistent (iOS has stripped BMP signatures entirely).