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Guide · Office and email

Why your email signature logo isn't showing, or arrives as an attachment, and how to fix it in Outlook, Gmail and iPhone Mail

By Blink Brief · Updated  · How pages are made

A signature logo reaches the reader in one of two ways. A linked logo is a web address that the reader's email app loads when the email opens, so it fails when the link isn't public, or when the app blocks pictures, which classic Outlook does by default. An embedded logo travels inside the email, so it always arrives, but many apps also list it as an attachment. For a linked logo, use a PNG or JPG at a public https:// link, no taller than 100 pixels for Gmail, then send a test to an Outlook, a Gmail and an iPhone address.

Short answer

  • Blank box or red X in Outlook: the reader's Outlook hasn't downloaded the pictures. They click the bar at the top of the email and choose Download Pictures. You can't change this from your side.
  • Broken picture in every app: the link needs a sign-in, opens a sharing page instead of the image, or the file has moved. The link checker below finds most of these.
  • Logo arrives as an attachment: it's embedded in the email. Link it from your website instead.
  • Logo too big or blurry: the file's pixel size doesn't match the size it's shown at. Gmail allows at most 100 pixels high.

Symptom, cause and fix

What the reader sees Usual cause Fix
A blank box or a red X in Outlook Classic Outlook blocks pictures from the internet until the reader allows them The reader chooses Download Pictures, or adds you to Safe Senders. Keep your contact details as text.
A broken picture in every app The link needs a sign-in, opens a Google Drive, Dropbox or OneDrive page, or the file was moved or deleted Use the image's own https:// address on your website, and check it below
The logo shows as an attachment The picture is embedded in the email: inserted from a file, or pasted with code that Outlook turns into an attachment Link the logo from your website. In classic Outlook, insert it again with the Image button.
No logo in Gmail, or Gmail won't save the signature The link isn't public, or the image is too big for the 10,000-character limit Make the link public and use a smaller image: Google recommends 70–100 pixels high
No logo in Apple Mail The reader blocks remote content, or the email landed in Junk The reader loads remote content for that email. Apple Mail never shows it in junk mail.
A blurry logo The file has fewer pixels than the space it's shown in Use a larger file, or show it smaller
A huge logo The signature sets no width, so the app shows the file at its own size Save a smaller copy, or set a width in the signature

From Microsoft, Google and Apple's help pages, read on 3 November 2026 and listed under Sources.

Linked or embedded: the two ways a logo travels

A linked logo is a picture whose address points to a file on a web server, such as https://yoursite.com/logo.png. The email carries only that address, and the reader's app fetches the file each time the email opens. Gmail's signature editor takes one by "Web Address (URL)", and signature generators, Blink Brief's included, write one.

An embedded logo is the picture file itself, packed into the email. Classic Outlook's Image button inserts a file from your computer, and Microsoft says images picked for a signature in the Outlook app on iPhone and Android are "downloaded and embedded into the signature".

  • Linked: small emails, no attachment icon, and you can swap the logo later by replacing the file at the same address. It needs a public link, and classic Outlook and Apple Mail with remote content blocked won't show it until the reader allows pictures.
  • Embedded: it arrives without a download, and Outlook's picture blocking covers pictures "from the Internet", so it doesn't hold back an embedded logo. Every email gets bigger, and many apps list the logo with the attachments.

For most people a linked PNG on your own website is the better trade: one file, small emails, no paperclip. The link has to open the image itself, for anyone, with no sign-in. Check yours here.

Check your logo link

To check it by hand:

  1. Open the link in a private browser window. It should show only the logo: no sign-in page and no website around it.
  2. Check that the link starts with https:// and ends in .png or .jpg.
  3. Most browsers show the image's size in pixels in the tab's title. Divide the height by the width and multiply by the width you show it at: that's its height in the signature. Keep it at 100 or less for Gmail.

Our product

Email Signature: a free generator in your browser, with no sign-up. It links your logo from the https:// address you give, warns on SVG, and says so when the image at your link won't load. It sets the logo's width from 40 to 200 pixels and lets the height follow, so check a square logo: at 120 pixels wide it's 120 high, over Gmail's 100. A linked logo is still blocked in classic Outlook until the reader downloads pictures; no generator can change that.

Open Email Signature

Outlook: blocked pictures, and logos that turn into attachments

Microsoft: "Microsoft Outlook is configured by default to block automatic picture downloads from the Internet." That's classic Outlook for Windows, and it's the reader's setting, not yours. What the reader can do, in Microsoft's steps:

  1. For one email: "Choose the InfoBar at the top of the message, and then select Download Pictures."
  2. For one sender: right-click a blocked picture and select Add Sender to Safe Senders List, or Add the Domain @domain to Safe Senders List.
  3. For every email: File › Options › Trust Center › Trust Center Settings, then clear Don't download pictures automatically in HTML e-mail messages or RSS items. In Outlook for Microsoft 365, the choices are on the Automatic Download tab.

On your side, write your name, phone number and website as text, not as part of the logo image, so the signature still reads while the picture is blocked. Give the picture alt text with your company's name, which screen readers read out; the free generator fills it in from your company name.

When Outlook turns the logo into an attachment

Microsoft's signature article warns: "Using Vector Markup Language (VML) tags in the signature can cause some elements to appear as attachments instead of inline images." VML often comes along when a signature is pasted from Word or a web page. Microsoft's fix is to insert the picture with the editor's own button:

  1. Open a new message, then select Signature › Signatures.
  2. Under Select signature to edit, choose your signature, and delete the old logo.
  3. Select the Image button, locate your logo file, and select Insert.
  4. Select OK, then OK again.

A logo added from the Outlook app on a phone is embedded by design, so some readers will see it as an attachment. The Outlook app guide covers it.

In Gmail's signature editor on a computer you add the logo one of three ways, in Google's words: Web Address (URL), "the URL of an image that is publicly available on the web"; My Drive, "a public image from your Google Drive"; or Upload, "an image file from your device". If one doesn't work, Google suggests trying the other two.

  • Drive images: "the image sharing settings must be set to public." On a work or school account you may need your administrator to allow it. "If the image file or a Google Doc in Drive with the image is deleted, the image won't show in the signature."
  • Length: "You can put up to 10,000 characters in your signature." And: "Your image also counts toward the character limit. If you get an error, try to resize the image."
  • Size: "We recommend a signature image that’s 70–100 pixels high by 300–400 pixels wide. The maximum size for email signature images is 100 pixels high by 1000 pixels wide." After adding the image, you can pick Small, Medium, Large or Original size in the editor.

On the reading side, Gmail shows images automatically by default, unless the reader chose Ask before displaying external images. Google adds: "If Gmail thinks a sender or message is suspicious, you won't see images automatically." The full Gmail steps for a team are in the team signature guide. If the logo goes missing only on mail sent from your phone, the Gmail app's own signature is the cause: see the Gmail app guide.

iPhone, iPad and Mac Mail: remote content and Privacy Protection

Apple Mail calls a linked logo "remote content". On a Mac, the settings are at Mail › Settings › Privacy:

  • Protect Mail Activity will "privately download remote content in the background when a message is received", so the logo shows.
  • With that off, Block All Remote Content holds back remote content "until you choose to do so".
  • "Remote content is never displayed in messages that are marked as junk."

On an iPhone or iPad, Mail Privacy Protection is at Settings › Apps › Mail › Privacy Protection, then Protect Mail Activity.

Sending from the iPhone is a separate problem. Apple's guide says "You can only use text in your Mail signatures," so a logo in the iPhone Mail signature often never leaves the phone. The iPhone Mail guide has the routes that work.

A blurry or huge logo: pixel size versus display size

Every logo has two sizes: the pixels in the file, and the size the signature shows it at. A logo looks blurry when the file has fewer pixels than the space it fills, and huge when the signature sets no width, so the app shows the file at its own size.

  • A 400 × 400 pixel logo shown 80 pixels wide is 80 × 80 in the email, and sharp.
  • The same logo shown 120 pixels wide is 120 pixels high: over Gmail's maximum of 100.
  • A wide 300 × 100 logo shown 150 pixels wide is 150 × 50, and the file has twice the pixels it needs, so it stays sharp on high-resolution screens.

If the logo has a lot of empty space around it, crop it first: the empty space counts toward the height.

A 5-minute test with three accounts

  1. Check the link with the checker above.
  2. Send yourself an email from the app you normally use, to an Outlook.com, a Gmail and an iCloud address. All three are free.
  3. Open each one on a computer and on a phone. In Outlook, note whether the logo waits for Download Pictures.
  4. Reply from each account, and look at the reply: a logo that turns into an attachment here will do the same for your clients.
  5. Fix one thing at a time with the table at the top, and send the test again.

Questions

Why does my email signature logo appear as an attachment?

Because the logo is embedded: the picture file travels inside the email, and many email apps list such files with the attachments. A logo linked from a public https:// address on your website isn't a file in the email, so it doesn't show up as one. In classic Outlook, Microsoft says VML code in a pasted signature can turn pictures into attachments, and its fix is to insert the picture again with the Image button.

Why is my email signature image not showing in Outlook?

Classic Outlook is "configured by default to block automatic picture downloads from the Internet", in Microsoft's words. The reader clicks the bar at the top of the email and chooses Download Pictures, or adds you to Safe Senders. Nothing in your signature can switch this off, so keep your name, phone and website as text.

Why is my Gmail signature image not showing on mobile?

The Gmail app has its own Mobile Signature. If you set one, the app uses it instead of the signature from your computer, and the app's box holds the text you type. Turn Mobile Signature off, and Google's help says new messages use the signature you set up on your computer. The Gmail app guide has the steps.

Why is my email signature image blurry?

The file has fewer pixels than the space it's shown in, so the app stretches it. Use a file at least as wide as the width set in the signature, and keep it within Gmail's maximum of 100 pixels high.

Does Outlook block images by default?

Classic Outlook for Windows does: Microsoft says it "is configured by default to block automatic picture downloads from the Internet." A logo embedded in the email isn't downloaded from the internet, so that setting doesn't hold it back.

Can I use an SVG logo in an email signature?

Not safely. Can I email lists Outlook 2007 to 2016 for Windows as not showing SVG at all, and Gmail as showing it only after turning it into a PNG, a change it first recorded in September 2026. Save the logo as a PNG or JPG.

Sources

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