Email Signature Image Size: Exact Pixels for Logos and Photos

For most email clients, an email signature logo should display at about 150–300 pixels wide and no more than 60–100 pixels tall, and a headshot at roughly 80–120 pixels square. Export the actual file at about twice that display size so it stays sharp on high-resolution screens, and keep each image small in kilobytes, ideally under 50 KB. You can get there in two steps: resize the image to exact pixels with the Image Resizer, then shrink the file with the Image Compressor.

That is the short answer. The rest of this guide explains why signature images so often turn up huge, blurry or as an attachment, which sizes suit logos, headshots and banners, and how to prepare each one so it looks the same in Gmail, Outlook and on a phone.

Why email signature image size matters

An email signature is sent with every message you write, so a badly sized image causes problems hundreds of times a week. The common complaints all trace back to size:

• The logo appears enormous. Some email clients, especially older desktop versions of Outlook, ignore the width you set in the editor and show the image at its real pixel size. A 2000-pixel-wide logo straight from a designer then fills the whole screen.
• The logo looks blurry. The opposite mistake: a 100-pixel image displayed at 200 pixels on a high-density laptop or phone screen gets stretched and soft.
• Every email feels heavy. A 1 MB PNG adds 1 MB to every message you send, and it can push long reply threads towards attachment limits.
• The image arrives as an attachment. Large or unusually formatted images are more likely to be shown as a paperclip attachment instead of inline, which looks unprofessional and confuses recipients.

Sizing the image correctly before you paste it into your email settings avoids all four problems at once.

Recommended email signature image sizes

There is no single official standard, because every email client renders HTML slightly differently. The ranges below are the ones most signature guides converge on, and they work well across the major clients.

Image type	Display size (width × height)	File to export (about 2×)	Target file size
Horizontal logo	150–300 × 40–80 px	300–600 × 80–160 px	Under 50 KB
Square logo or icon	60–100 × 60–100 px	120–200 × 120–200 px	Under 30 KB
Headshot photo	80–120 × 80–120 px	160–240 × 160–240 px	Under 50 KB
Promotional banner	up to 600 × 100–150 px	up to 1200 × 200–300 px	Under 100 KB
Social media icons	16–24 × 16–24 px	32–48 × 32–48 px	A few KB each

Keep the whole signature to about 600 pixels wide or less. That is the width most email templates are designed around, and anything wider forces horizontal scrolling on phones.

Why export at twice the display size?

Modern laptops and almost every smartphone use high-density screens that pack two or three physical pixels into each "CSS pixel". If your logo is meant to appear 200 pixels wide and the file is exactly 200 pixels wide, those screens have to stretch it, and the edges of text in the logo go soft.

Exporting a 400-pixel-wide file and telling the email editor to show it at 200 pixels gives the screen enough detail to stay crisp. The catch is Outlook for Windows, which sometimes ignores the display width and shows the image at its full 400 pixels. If your recipients mostly use Outlook on Windows, a safer compromise is to export at exactly the display size, or at 1.5×, and accept slightly softer edges on Retina screens.

How to resize a signature image to exact pixels

Most people start with a logo file that is far too large. Here is how to bring it down to a precise size without installing anything.

1. Start from the best original you have. Use the highest-quality PNG or JPG version of the logo. Avoid screenshots of a website or a PDF, which are already blurred.
2. Crop away empty space first. Logos often come with wide transparent or white margins. Trim them with the Image Cropper so the logo itself fills the frame, otherwise it will look tiny at signature size.
3. Resize to your target width. Open the Image Resizer and enter only the width you chose (for example 400 pixels for a logo displayed at 200); leave the height empty and it follows the original proportions automatically. If you fill in both, the image is stretched to exactly that size, so only do that after cropping to the matching shape.
4. Compress the result. Run the resized file through the Image Compressor. For a small logo this usually takes it into the tens of kilobytes with no visible change.
5. Upload or paste it into your signature settings and, if the editor allows it, set the display width to half the file width.
6. Send a test email to yourself and to an account on a different client, and check it on a phone as well as a desktop.

Toolyfied's image tools are free, need no sign-up and add no watermark. The resizer and compressor process the upload on Toolyfied's server; files are used only to produce your result and old files are cleaned up automatically every day.

PNG, JPG or something else?

The format matters almost as much as the dimensions.

• PNG is the right choice for logos, icons and anything with flat colours, sharp text or a transparent background.
• JPG suits photos, such as a headshot. It gives much smaller files for photographic images but cannot hold transparency.
• GIF is widely supported, but its limited colour palette makes logos with gradients look banded. Use it only for very simple graphics.
• SVG and WebP are not reliably supported in email clients. A signature built with them may show a broken image for some recipients, so convert to PNG or JPG first.

If your designer only gave you a WebP file, convert it with the WebP to PNG converter, which keeps transparency, before resizing.

A note on transparent backgrounds and dark mode

A transparent PNG logo looks clean on a white email, but many people read mail in dark mode. A black logo on a transparent background can disappear against a dark grey screen. Two simple fixes: give the logo a white or light rounded background shape, or add a thin light outline around dark lettering. If you need to remove a messy background from a photo of a logo in the first place, the Background Remover uses AI to produce a transparent PNG you can then resize.

Headshots: getting a photo to look professional at tiny sizes

A headshot in a signature is usually shown at around 80–120 pixels. At that size, detail disappears quickly, so a few habits help:

• Crop tightly to head and shoulders. A full-body photo becomes an unrecognisable figure at 100 pixels.
• Crop to a square first, even if your email client will show it as a circle.
• Save as JPG rather than PNG; a photographic PNG can easily be ten times larger for the same look.
• Avoid busy backgrounds, which turn into visual noise when shrunk.

Gmail and Outlook specifics

Gmail lets you insert an image into a signature from Google Drive or a public URL, and then choose small, medium or large in the editor. Those presets scale the picture for display, but the original file still matters for sharpness and weight, so prepare it at the right size first. Gmail also limits the total length of a signature, so very large inline images can be rejected.

Outlook behaves differently across its versions. The web and newer apps generally respect the size you set, while older Windows desktop versions are the ones most likely to show an image at its native pixel size or to display it as an attachment. Testing on the version your recipients use is the only reliable check.

Apple Mail and most phone mail apps handle well-sized PNG and JPG images without fuss, which is another reason to stay with those two formats.

Quick checklist before you save your signature

• Whole signature no wider than about 600 pixels.
• Logo file roughly 300–600 pixels wide, displayed at 150–300.
• Headshot cropped square, around 160–240 pixels, saved as JPG.
• Each image ideally under 50 KB, the whole signature well under 100 KB.
• PNG for logos, JPG for photos, no SVG or WebP.
• Tested in at least two email clients, in light and dark mode, on desktop and phone.

Ten minutes spent sizing the images correctly means your signature looks deliberate in every inbox, instead of oversized, fuzzy or stuck at the bottom of the email as an attachment.