Best Image Size for Email Signatures

Recommended Image Dimensions

Company Logos

• Standard Size: 200x80 pixels (width x height)
• Maximum Width: 300 pixels (to avoid taking up too much space)
• Aspect Ratio: Maintain your logo's original aspect ratio
• File Format: PNG (supports transparency) or JPEG
• File Size: 20-50KB (compress without losing quality)

Why these dimensions? Logos at 200px width are large enough to be clearly visible but small enough to not dominate the signature. The 80px height keeps the signature compact while maintaining logo readability.

Profile Photos

• Standard Size: 150x150 pixels (square)
• Alternative: 120x120 pixels for more compact signatures
• Maximum: 200x200 pixels (larger photos take up too much space)
• File Format: JPEG (better compression for photos)
• File Size: 30-80KB

Why square? Square photos work best in email signatures because they fit well in the layout and look professional. Circular photos can be achieved with CSS border-radius, but square source images are more reliable.

Social Media Icons

• Standard Size: 24x24 pixels or 32x32 pixels
• File Format: PNG (for transparency and crisp edges)
• File Size: 2-5KB per icon

Tip: Use icon fonts or SVG converted to PNG for crisp, scalable social media icons. Many email signature tools provide pre-optimized social icons.

Banner Images or Graphics

• Maximum Width: 600 pixels (matches email width)
• Height: 100-150 pixels (keep it compact)
• File Format: JPEG or PNG
• File Size: 50-100KB

Note: Banner images are less common in professional signatures. Use sparingly and only if they add value without cluttering the signature.

File Size Guidelines

Total Signature Size

• Recommended Total: Under 100KB for all images combined
• Maximum: 150KB (some email clients may block larger signatures)
• Ideal: 50KB or less for fastest loading

Why File Size Matters

• Loading Speed: Smaller files load faster, especially on mobile devices
• Email Client Limits: Some email clients block or delay loading of large images
• Mobile Data: Recipients on mobile data appreciate smaller file sizes
• Spam Filters: Very large signatures may trigger spam filters

Image Format Best Practices

PNG (Portable Network Graphics)

Best for: Logos, icons, graphics with transparency

• Supports transparency (useful for logos)
• Lossless compression (no quality loss)
• Larger file sizes than JPEG
• Use PNG-8 for simple graphics, PNG-24 for photos with transparency

JPEG (Joint Photographic Experts Group)

Best for: Photos, complex images

• Better compression for photos (smaller file sizes)
• No transparency support
• Quality loss with compression (find the right balance)
• Use quality setting of 80-90% for good balance

GIF

Best for: Animated images (rarely used in signatures)

• Supports animation
• Limited color palette (256 colors)
• Not recommended for static images (use PNG or JPEG instead)

Image Optimization Tips

Compression

• Use Tools: Tools like TinyPNG, ImageOptim, or Squoosh can reduce file sizes by 50-80% without noticeable quality loss
• JPEG Quality: For photos, quality of 80-85% is usually sufficient
• PNG Optimization: Use PNG-8 for simple graphics, PNG-24 only when you need full color and transparency

Responsive Images

• Use CSS: Set max-width: 100% and height: auto to make images responsive
• Retina Displays: For high-DPI displays, you can use 2x images (e.g., 400x160px for a 200x80px logo), but this increases file size
• Mobile First: Optimize for mobile viewing first, as most emails are read on mobile devices

Hosting

• Reliable Hosting: Host images on your website, CDN, or reliable image hosting service
• HTTPS Required: Use HTTPS URLs (https://) for images - many email clients block HTTP images
• Absolute URLs: Always use full absolute URLs, not relative paths
• CDN Benefits: Content Delivery Networks (CDNs) can speed up image loading globally

Common Mistakes to Avoid

Using Images That Are Too Large

• Problem: Large source images (e.g., 2000x2000px) scaled down in HTML
• Issue: Large file sizes slow down loading, even if displayed small
• Solution: Resize images to their display size before adding to signature

Not Compressing Images

• Problem: Using uncompressed images straight from camera or design software
• Issue: File sizes can be 500KB+ for a single image
• Solution: Always compress images before using in signatures

Using Wrong Format

• Problem: Using JPEG for logos (no transparency) or PNG for photos (larger files)
• Issue: Suboptimal file sizes or missing features (like transparency)
• Solution: Use PNG for logos/graphics, JPEG for photos

Relative Image Paths

• Problem: Using relative paths like "/images/logo.png"
• Issue: Images won't load in email clients (they can't resolve relative paths)
• Solution: Always use absolute URLs: "https://yoursite.com/images/logo.png"

Too Many Images

• Problem: Including multiple large images in one signature
• Issue: Total file size becomes too large, slow loading
• Solution: Limit to 2-3 images max, keep total size under 100KB

Testing Your Images

Before finalizing your signature, test your images:

1. File Size Check: Verify each image is under the recommended size
2. Display Test: Send yourself a test email and check how images look
3. Mobile Test: Check signature on mobile device to ensure images load and display correctly
4. Multiple Clients: Test in Gmail, Outlook, Apple Mail to ensure compatibility
5. Loading Speed: Check how quickly images load (should be instant)
6. Broken Images: Verify no broken image icons appear

Quick Reference Table

Frequently Asked Questions

Next Steps

Now that you know the optimal image sizes:

• Create a professional signature with BrandaSign (we handle image optimization automatically)
• Troubleshoot image display issues
• Learn how to add images to Gmail signatures