Where to find the signature settings in your email program
Most email programs store signature settings in the same place: your account preferences or settings menu. The exact path depends on whether you use Gmail, Outlook, Apple Mail, or another service, but the principle is the same — you create the signature once, and it attaches to every email you send.
In Gmail, click the gear icon in the top right, select "See all settings," then go to the "Signature" tab. In Outlook on the web, select the gear icon, then "Mail" > "Compose and reply" > "Signatures." In Outlook desktop, go to "File" > "Options" > "Mail" > "Signatures." On Apple Mail, open Mail preferences, click the "Signatures" tab, then select your email account. Each program lets you create multiple signatures and choose which one appears by default.
If you use a different email service, search "[your email service] how to add signature" — the setting exists in nearly every program, though the menu path varies. Some services like ProtonMail or Tutanota have signature options in account settings rather than compose settings.
Key Takeaways
- Most email programs require you to upload or paste an image file into the signature editor, not link to an external image.
- A logo in your signature should be small — typically 50 to 100 pixels tall — so it does not make your signature take up half the screen.
- Some email clients strip images from signatures or display them unreliably, so test your signature on a phone and in different email programs before relying on it.
- If your logo does not appear in received emails, your email service may have image-blocking enabled, or the recipient's email client may not support embedded images.
Uploading an image file versus linking to one
Email signatures handle images in two ways: embedded (the image is stored inside the email itself) and linked (the email points to an image hosted somewhere else). Embedded images are more reliable because they travel with the email and display even if the recipient's email client blocks external images. Linked images are smaller files but may not show up if the recipient's email program has image-blocking turned on.
Most email services default to embedding images. When you add a logo in Gmail, Outlook, or Apple Mail, the program usually uploads the image and stores it on their servers, then embeds it in your signature. You do not need to host the image yourself. If you want to link to an image instead — for example, a logo hosted on your company website — check whether your email service offers that option in the signature editor. Gmail and Outlook both allow it, but the image must be publicly accessible (not behind a login).
For the most reliable result, use an embedded image. It takes slightly more storage but ensures your logo appears the same way to everyone who receives your email.
Resizing your logo so it does not overwhelm the signature
A logo in an email signature should be small enough that it does not dominate the message. Most professional signatures keep the logo between 50 and 100 pixels tall — roughly the height of a line of text or slightly taller. A logo that is 200 pixels tall or more will make your signature take up a quarter of the screen on a phone, which looks unprofessional and wastes space.
Before you upload, resize your logo file using an image editor. On Windows, right-click the image, select "Open with" > "Photos," then use the crop tool to resize. On Mac, open the image in Preview, click "Tools" > "Adjust Size," and set the height to 50 to 100 pixels. If you do not have an image editor, upload the logo to a free online tool like Pixlr or Canva, resize it there, and read the result.
After you add the logo to your signature, send yourself a test email and check how it looks on your phone. If it is still too large, go back to the signature settings, delete the image, resize it smaller, and upload it again. Most email services do not let you resize the image directly in the signature editor.
Supported image formats and file size limits
Email programs accept most common image formats: JPG, PNG, GIF, and WebP. PNG is usually the best choice for logos because it supports transparent backgrounds (so your logo does not sit in a white box) and compresses well without losing quality. JPG works if your logo has a solid background. Avoid BMP or TIFF — some email clients do not display them reliably.
File size matters because large images slow down email delivery and take up storage space. Keep your logo under 100 kilobytes (KB). If your logo file is larger, compress it before uploading. Most image editors have an "export" or "save for web" option that reduces file size automatically. Online tools like TinyPNG or Compressor.io also compress images without visible quality loss.
Gmail, Outlook, and Apple Mail all accept images up to several megabytes, so file size is rarely a hard limit — but a smaller file is always better for email. Test your signature on a slow internet connection to make sure the image loads quickly.
Why your logo might not appear in received emails
Even after you add a logo to your signature, it may not show up in every email the recipient receives. The most common reason is that the recipient's email client has image-blocking turned on. Many email programs, including Gmail and Outlook, block external images by default to protect privacy and prevent tracking. If your logo is linked rather than embedded, it will not display when images are blocked.
If you embedded the image (which most services do by default), it should display even with image-blocking on — but some email clients are aggressive and block all images, including embedded ones. There is nothing you can do about this on your end. The recipient can choose to display images, but that is their decision.
Another reason logos fail to appear is that the recipient is using a very old email client or a mobile app that does not support images in signatures. Some corporate email systems also strip images from outgoing mail for security reasons. If you need your logo to appear reliably, ask a few colleagues or clients to check whether they see it — if most do, the issue is on the recipient's end.
Adding a logo alongside text in your signature
Most email services let you mix text and images in a signature. You can put your name and contact information above the logo, below it, or to the side. The exact layout depends on your email program's signature editor.
In Gmail, the signature editor is a straightforward text box with a toolbar. Click the image icon in the toolbar, upload your logo, then type your name and contact details around it. You can press Enter to move text above or below the image. In Outlook on the web, the editor is similar — type your text, then use the "Insert" menu to add an image. In Outlook desktop, you get more control over layout; you can create a table to position text and images side by side.
Keep the signature clean and straightforward. A typical professional signature includes your name, job title, company name, phone number, and email address — plus the logo. Do not add multiple images, decorative lines, or large blocks of color. The goal is to make your contact information straightforward to read, not to impress with design.
Testing your signature on different devices and email clients
Before you rely on your signature in real emails, test it on the devices and email programs your contacts actually use. Send yourself a test email from your account, then open it on your phone, tablet, and computer. Check whether the logo appears, whether the text is readable, and whether the spacing looks right.
If you have colleagues or friends who use different email clients, ask them to send you a test email so you can see how your signature appears in their inbox. Gmail displays signatures differently than Outlook, which displays them differently than Apple Mail. A signature that looks perfect in Gmail might have alignment issues in Outlook.
Pay special attention to mobile. Many people check email on their phone, and a signature that looks fine on desktop can become cramped or misaligned on a small screen. If your logo is too large or your text is too small, adjust it and test again.
Frequently Asked Questions
Can I use a company logo that is not square?
Yes. Logos come in all shapes — horizontal rectangles, vertical rectangles, circles, and irregular shapes. When you resize your logo, keep its original proportions so it does not look stretched. If your logo is very wide and short, you may need to make it taller than 100 pixels to keep the text readable, but try to stay under 150 pixels.
What if I want different signatures for different email accounts?
Most email services let you create multiple signatures and assign them to different accounts. In Gmail, create one signature per account in the Signature settings. In Outlook desktop, go to "Signatures," create a new one, then assign it to the account you want in the "Choose default signature" dropdown. You can then pick which signature to use when you compose each email.
Does adding a logo to my signature increase the file size of every email I send?
Yes, but not by much if you resize the logo properly. A 50-pixel logo that is 50 KB adds about 50 KB to each email. That is small enough that it does not affect delivery speed or storage limits for most people, but it does add up if you send hundreds of emails per month. If file size is a concern, keep the logo under 30 KB.
Can I add a clickable link to my logo?
Yes. In most email editors, right-click the image after you upload it and select "Add link" or "Insert hyperlink." Paste the URL you want the logo to link to — usually your company website or LinkedIn profile. When someone clicks the logo, it opens that link. This works in Gmail, Outlook, and Apple Mail, though some email clients may not support clickable images in signatures.
Why does my logo look blurry in some emails?
Blurriness usually means the original image file was too small and got enlarged to fit your signature. If your logo is 50 pixels wide and you resize it to 100 pixels in the signature editor, it will look pixelated. Always start with a logo file that is at least as large as the size you want to display, then resize it down if needed. If you only have a small version of your logo, ask your company or designer for a higher-resolution version.