Email Signature Image Not Showing
A broken image in your email signature — a grey placeholder where your logo or headshot should be — is worse than having no image at all. It signals technical incompetence to every recipient. The fix depends on which email client is causing the problem and how the image is referenced in your signature's HTML.
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Diagnose the Problem
Image shows for you but not for recipients
Likely cause: Authenticated URL
Your image is hosted on a source that requires login (SharePoint, Google Drive with restricted access, corporate intranet). Recipients can't access it. Move the image to a public HTTPS URL — your website, Cloudinary, or any public CDN.
Image doesn't show in Gmail but works in Outlook
Likely cause: Base64 encoding
Gmail strips base64-encoded images from signatures. Replace data:image/... URLs with a hosted HTTPS image URL. Gmail will proxy the image through its own CDN (lh3.googleusercontent.com) — this is normal.
Image shows as a tiny broken icon
Likely cause: URL is broken or image deleted
The image URL returns a 404 error. Open the URL directly in your browser. If it doesn't load, the image has been moved or deleted. Re-upload and update the src URL in your signature.
Image is way too large or too small
Likely cause: Missing width attributes
Add both width='80' (HTML attribute) and style='width:80px;max-width:80px;' (inline CSS). Without these, Outlook scales the image based on Windows DPI settings, and Gmail uses the image's native pixel dimensions.
Image shows for some recipients but not others
Likely cause: Recipient's client blocking images
Many email clients (especially Outlook in corporate environments) block external images by default. Recipients see a placeholder until they click 'Download images'. You cannot fix this on your end — it's a recipient-side security setting. Ensure your alt text is descriptive so the placeholder is meaningful.
Image was working but suddenly stopped
Likely cause: Hosting URL changed
If you use a CDN or cloud storage, the URL may have changed after a migration, expiry, or policy change. Check if the URL still resolves. Re-upload if necessary.
Correct Image HTML
This pattern works across all email clients:
src: HTTPS URL — Must be publicly accessible. No base64, no HTTP, no file:// paths.
width + height HTML attributes — Fixes Outlook DPI scaling. Prevents layout shift.
alt text — Shows when images are blocked. Use descriptive text, not empty string.
display:block — Removes phantom gap below image in email clients.
border:0 — Prevents blue border around linked images.
Where to Host Signature Images
RELIABLE HOSTS
- okYour company website (/images/logo.png)
- okCloudinary (free tier, stable URLs)
- okCloudflare Images
- okAWS S3 (public bucket or CloudFront)
- okGitHub Pages / Vercel / Netlify
AVOID THESE
- noGoogle Drive (unstable URLs, auth issues)
- noOneDrive / SharePoint (requires login)
- noDropbox direct links (rate limited, auth)
- noBase64 inline data (Gmail strips it)
- noLocal file paths (file://)
Testing Your Image
Open your image URL in an incognito/private browser window — does it load? If not, it's not public.
Send a test email to a Gmail account and an Outlook account. Check both.
Ask someone outside your organisation to check if they can see the image.
Right-click the image in your email client → 'Copy image address' → paste in browser to verify the URL.
Related Guides
Fix Your Signature Images
Generate a signature with correctly hosted, properly formatted images. Free, no signup.
Create My Signature →Works with Gmail, Outlook, Apple Mail & more