Picovert

Email Signature Image Size — Logo, Banner, and Photo Dimensions

By Picovert Team2026-03-134 min read

Email signature images need to be small enough to load quickly in any email client — including Gmail, Outlook, Apple Mail, and mobile — while still looking sharp on retina displays. The most common mistake is uploading a large image and letting the email client scale it down, which results in blurry images or slow-loading emails that get flagged as spam. This guide covers the correct dimensions for every type of email signature image.

Email Signature Image Sizes — Quick Reference

  • Company logo: 300×100 px at 2× (150×50 px display size)
  • Banner / promotional image: 600×150 px maximum
  • Headshot / profile photo: 100×100 px (display size)
  • Social media icons: 20×20 px each
  • File format: PNG for logos, JPG for photos
  • Max file size: under 50 KB per image, under 100 KB total

Company Logo Size in Email Signature

A company logo in an email signature typically displays at 150×50 px or 200×66 px. To look sharp on retina (high-DPI) screens, upload the image at 2× resolution:

  • Upload at: 300×100 px or 400×133 px (2× the display size)
  • HTML width attribute: set to half the pixel width (e.g., width="150" for a 300 px wide image)
  • File format: PNG for logos with transparency or text; JPG for photographic logos
  • File size: under 20 KB

Never use SVG in email signatures — most email clients don't support it. Stick to PNG or JPG.

Email Signature Banner Size

Promotional banners in email signatures (e.g., "Join our webinar" or seasonal promotions) should match the width of the email:

  • Recommended width: 600 px (matches standard email body width)
  • Height: 100–200 px. Keep it short — a tall banner pushes the signature too far down the email.
  • File size: under 50 KB
  • File format: JPG for photos, PNG for graphics with text

Outlook clips images wider than 800 px. Gmail on mobile scales signatures to fit the screen. A 600 px banner is safe across all clients.

Headshot / Profile Photo in Email Signature

A professional headshot in an email signature makes emails more personal:

  • Display size: 80×80 px to 100×100 px
  • Upload at: 200×200 px (2× retina) — crop to square first
  • Shape: Square or circle (circle is done with CSS border-radius: 50% in the signature HTML)
  • File format: JPG
  • File size: under 20 KB

Why Email Signature Images Must Be Small

Large images in email signatures cause several problems:

  • Spam filters: Emails with large images and little text trigger spam filters. Keep the image-to-text ratio balanced.
  • Slow loading: Recipients on mobile or slow connections see a blank space while the image loads. Images over 100 KB slow down inbox rendering noticeably.
  • Blocked by default: Outlook and many enterprise email clients block external images by default. Your signature may look broken until the recipient manually allows images.
  • Storage: Each sent email stores a copy of embedded images. Sending 1000 emails with a 500 KB image wastes 500 MB of server storage.

How to Resize Images for Email Signatures

  1. Open Picovert's image resizer — free, no account needed.
  2. Set the target dimensions: 300×100 px for a logo (2× retina), 200×200 px for a headshot (2× retina), 600×150 px for a banner.
  3. If the proportions are off, crop to the right ratio first using the crop tool.
  4. After resizing, compress the image using Picovert's compressor to get under 50 KB.
  5. Save as PNG for logos, JPG for photos.

PNG vs JPG for Email Signature Images

  • Use PNG for logos, icons, and images with text. PNG preserves sharp edges and supports transparency, so logos with transparent backgrounds display correctly on any email background color.
  • Use JPG for photos and headshots. JPG produces much smaller files for photographs — a 200×200 headshot is 8–15 KB as JPG vs 30–60 KB as PNG.
  • Avoid GIF unless you need simple animation. Animated GIFs in signatures can be distracting and are often blocked.
  • Avoid WebP — Outlook 2019 and Apple Mail on older macOS versions don't display WebP images.

Email Signature Image Best Practices

  • Host images externally rather than embedding them. External images load from a URL and don't add to email file size. Use your company website or a CDN.
  • Always set width and height attributes in the HTML. This reserves space while the image loads and prevents layout shift.
  • Add alt text to every image. If images are blocked, the alt text shows your name and company instead of a broken image icon.
  • Test on multiple clients: Gmail, Outlook, Apple Mail, and mobile. Signature rendering varies significantly between clients.