How to Resize Image for Email Signature

An email signature image — whether it's your company logo, a headshot, or a promotional banner — is sent with every email you write. If it's too large, it looks clunky and can even trigger spam filters. Too small and it looks blurry on Retina displays. Getting the size right takes just seconds with the right tool.

Recommended Email Signature Image Sizes

Email clients display images at 72–96 DPI on standard screens. For standard logos, aim for a width of 200–300 pixels. For Retina/HiDPI displays, double that to 400–600 pixels wide and set your image's CSS width to half. Promotional banners should be 600px wide — the standard maximum email width.

How to Resize an Image for Your Email Signature

1. Open the Image Resizer at imgresizr.com.
2. Upload your logo or headshot.
3. Set the width to 300px (logo) or 150px (headshot).
4. Enable Lock Aspect Ratio so the height scales proportionally.
5. Download the resized image as PNG (for logos with transparency) or JPG (for photos).
6. Compress it to under 100 KB to avoid email deliverability issues.

Tips for Email Signature Images

Compress for Deliverability

Large image attachments in email signatures can cause emails to land in spam folders or be blocked by corporate mail servers. Always compress your signature image to under 100 KB. Use PNG for logos with transparent backgrounds and JPG for photos.

Host Images Externally

Rather than embedding images, host them on your website and reference them via URL. This keeps your emails lightweight and ensures the image always loads fresh. Most professional email clients handle hosted images well.