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Email Signature Image Size: Specs for Logos, Ohotos, and Banners

Get the correct pixel dimensions, resolution, and file weight for logos, profile photos, and banners in your email signature. See exact specs

Reading time: 4 min Author: amotz.harari@wisestamp.com Updated: April 27, 2026
Email Signature Image Size Guidelines

Short Answer

What is the correct email signature image size?

Image typeDimensions (px)FormatMax file size
Horizontal logo150-200 wide x 70-100 highPNGUnder 120KB
Square/circular logo150-200 x 150-200PNGUnder 120KB
Profile photo80-100 x 80-100PNG or JPGUnder 120KB
Promotional banner600 wide x 100-200 highPNG or JPGUnder 120KB

Export every image at 2x your intended display size. Target 72dpi resolution.

Risk of Wrong image size

Wrong image sizes quietly undermine your brand across every email

Image sizing is something most brand managers address at the template level: fonts, colors, layout. Individual image assets often get skipped entirely.

The result lands in inboxes. A logo that renders correctly in one test but breaks on a colleague’s iPhone. A profile photo that looks fine in Outlook desktop but appears blurry in Gmail.

These aren’t isolated glitches. Every employee’s outgoing email carries those images. At 100 employees sending 50 emails each per day, that’s 5,000 brand impressions. Sharp or broken.

Why wrong image sizes quietly undermine brand across every email

Logo Sizing

How to size an email signature logo correctly

Logo dimensions depend on orientation. A horizontal logo should sit between 150-200px wide and 70-100px high. A vertical logo reverses those proportions. A square or circular logo works well at 150-200px on both dimensions.

How a horizontal logo sits in an email signature — display dimensions at 150–200px wide

For vertical logos, the same proportions apply in reverse: 70-100px wide and 150-200px high. The 2x export rule applies regardless of orientation.

Vertical logo orientation in an email signature, shown with a promotional banner below

Most mobile email clients render at roughly 400px wide. A logo wider than 200px will push your contact details and CTAs below the fold on smaller screens.

How an oversized logo gets cut off on mobile — a 460x175px logo displayed on a 400px-wide screen

The sharpness trick: export at 2x your target display size. If you want the logo to display at 150px wide, save it at 300px. This doubles pixel density without adding visual bulk.

Our nice new Bizzabo logo is now very visible in every email we send, which considerably increases our brand recognition.

Amanda Gratz, Design Operations Manager at Bizzabo

Resolution And Format

Which file format and resolution work best for email signature images?

PNG is the right format for logos and profile photos. It preserves transparent backgrounds and renders crisply across Gmail, Outlook, and Apple Mail.

Resolution should be set to 72dpi. Email clients display at screen resolution; higher settings add file weight without visible benefit.

File weight affects deliverability. MailJet recommends keeping individual images under 120KB to prevent slow loading and spam filter friction. TinyPNG compresses images without visible quality loss and handles up to 20 files at once for free.

If your logo exists as a vector file (SVG, EPS, or AI), start there when resizing. Vector formats scale without quality loss and give you clean PNG exports at any size from Figma, Photoshop, GIMP, or Canva.

Email signature image resolution checklist

Managing Images At Scale

How can I handle email signature image sizing company-wide?

Getting image sizing right for one signature is straightforward. Keeping it consistent across 50, 200, or 1,000 employees is a different problem.

WiseStamp’s Studio editor lets you upload a logo or banner once and control how it displays across every employee’s signature. When you update the image, it pushes to every assigned mailbox instantly.

A marketing manager I spoke with summed it up this way: “Mobile and desktop signatures finally looked the same. That alone sold it for us.”

The same workflow applies whether you’re rolling out to a 1,000-person team or a 17,000-person enterprise.

See how WiseStamp manages signature images across your team

Takeaway

Email signature image size: the specs that matter

Logo: 150-200px wide. Profile photo: 80-100px square. Banner: 600px wide. Export every image at 2x display size, set to 72dpi, and keep files under 120KB. Use PNG for logos and profile photos. Compress with TinyPNG before uploading.

FAQ

What dimensions should an email signature logo be?

Email signature logo dimensions depend on the logo’s orientation:

– Horizontal logo: 150-200px wide, 70-100px high
– Square or circular logo: 150-200px on each side
– Vertical logo: 70-100px wide, 150-200px high

Most mobile email clients render at roughly 400px wide. Logos wider than 200px push contact details below the fold on smaller screens.

What is the ideal email signature image resolution?

72dpi is the correct resolution for email signature images. Higher DPI adds file weight without visible benefit. Email clients display at screen resolution regardless of the original image DPI setting.

Why do email signature images appear blurry?

Email signature images appear blurry when the image file is exported at its intended display size instead of 2x. Export at twice the intended display size, then constrain width in your signature editor. A logo meant to display at 150px should be saved at 300px.

What file format should email signature images use?

PNG is the recommended format for email signature logos and profile photos. PNG supports transparent backgrounds, preventing white boxes on colored email backgrounds or in dark mode. JPG is acceptable for profile photos where transparency is not needed.

How large should email signature image file sizes be?

Keep each email signature image under 120KB. MailJet recommends this threshold to prevent slow loading and spam filter friction. TinyPNG compresses images without visible quality loss and handles up to 20 files at once for free.

What causes email signature images to change size across email clients?

Email signature images resize incorrectly when HTML display dimensions conflict with the original file dimensions. Some email clients, including certain Outlook versions, ignore HTML resize instructions and render the original file size. Resize the image file before uploading rather than relying on the signature builder’s resize controls.

What is the correct email signature banner image size?

Email signature promotional banners should be 600px wide and 100-200px high. Keep the file under 120KB. PNG works well for banners with logos or text; JPG suits photo-based banners.

What is the correct profile photo size for an email signature?

Email signature profile photos should be 80-100px square. Export at 2x that size (160-200px) for sharpness on high-resolution screens. PNG is better when the photo is cropped to a circle or non-rectangular shape; JPG is fine for standard rectangular crops.

Does dark mode affect how email signature images are displayed?

Dark mode can invert or alter email signature images with solid white backgrounds, making logos appear with dark boxes or disappear entirely. PNG files with transparent backgrounds render correctly in dark mode across Gmail, Apple Mail, and Outlook.

What tools can resize email signature images correctly?

The following tools resize email signature images correctly:

– Figma (web and desktop, free plan available)
– Adobe Photoshop (desktop, paid)
– GIMP (desktop, free)
– Pixlr (web, free)
– Canva (web, free plan available)

If your logo is a vector file (SVG, EPS, or AI), open it in any of these tools and export as PNG at the target size.

Should email signature images be hosted externally or embedded in the email?

Email signature images are typically hosted externally via a URL rather than embedded inline. Inline embedding as Base64 significantly increases email file size and affects deliverability. Most signature management platforms, including WiseStamp, host images on their servers and reference them via URL in the signature HTML.

What happens to email signature images when an email is forwarded?

Email signature images may not display correctly in forwarded emails, depending on the recipient’s email client. Externally hosted images load more reliably than embedded ones. Some clients strip images in forwarded threads entirely. Inconsistent image rendering in forwarded emails is a known email client limitation, not a resizing issue.

Can WiseStamp resize email signature images automatically?

WiseStamp’s Studio editor handles email signature image display sizing within the template. Admins upload a logo or banner once, and WiseStamp controls rendering across Gmail, Outlook, and Exchange. Image updates push to all assigned employees instantly on publish.

What is the best image format for animated GIFs in email signatures?

GIF is the only email signature image format that supports animation. Animated GIFs display in Gmail, Apple Mail, and most mobile email clients. Outlook for Windows replaces animated GIFs with a static first frame. Keep animated GIF files under 500KB to avoid deliverability issues.