Can't see images in an email? Styled alt text shows a headline.

Styled alt text is an image's alternative text with a set font, colour and size, which the email program shows as a headline when the image does not load. Thanks to it, the email still makes sense to recipients whose program blocks images, for example in classic Outlook or Thunderbird. All you need to do is fill in the image's alt text and set its appearance in the Quanda email editor. Instead of an empty frame, the recipient then reads a prominent headline, such as “Autumn sale: 30% off”. In this article you will find which programs block images, a big comparison of where styled alt text is shown, and how to set it up in Quanda.

Key takeaways

1. Classic Outlook for Windows and Thunderbird block images by default. Gmail hides them in suspicious messages and any recipient can turn them off.
2. That is why every image needs alt text. Without it, the image leaves nothing but empty space.
3. The Quanda email editor can also style the alt text: you choose the font, colour, size, bold and alignment.
4. A program that supports styled alt text shows it as a prominent headline instead of the image. The recipient does not just see empty space.
5. Styled alt text is shown by Gmail, Mail on iPhone and iPad, Apple Mail, Thunderbird, Outlook.com and Seznam.cz. Based on Litmus market share, that covers roughly 91% of opens.
6. Classic Outlook for Windows shows alt text only as plain text. Put the important words first.

In short: what it is, what to do, how to set it up and what to watch out for

• What it is: alt text with a set font, colour and size that is shown as a headline in place of an image that did not load.
• What to do: fill in the alt text and style it as a headline in Quanda.
• How to set it up: in the Quanda email editor, in the image's right panel, the Image title field and the Set appearance switch.
• Watch out: some programs crop text that does not fit into the image area or do not show it at all.

What has changed since the article was published: The article first came out in October 2021. The claim that most email clients block images no longer holds. Gmail, Apple Mail and Yahoo now load them automatically, and the programs that block them by default are mainly classic Outlook and Thunderbird. We added an overview of today's programs based on their documentation and current market share figures from Litmus. We split the original styled alt text support tables into webmail, desktop programs and mobile apps, removed programs that are no longer in use, such as BlackBerry and Windows Phone devices, and added a coverage calculation based on share of opens. New sections cover how to write alt text and how to set it up in Quanda step by step.

What alt text and styled alt text are

Alt text is a short text description of an image that is shown in its place when the image does not load. Technically it is the alt attribute of the img tag in the email's HTML code, hence the name. It is also called alternative text, and in Quanda you will find it as the Image title.

Styled alt text is alt text with its own font, size, colour and other appearance settings. Without styling, alt text appears in small type in the default colour, and hardly anyone notices it. With styling, it becomes a headline that at first glance looks like part of the email. This is exactly what the Quanda email editor can do on top of the basics: you do not just fill in the alt text, you style it too.

Alt text has two jobs:

• Replacing the image. When the email program does not download an image or the image fails to load, it shows the alt text in its place. The recipient still knows what you want to tell them.
• Accessibility. Screen readers used by blind and partially sighted people read alt text aloud. Without it, the screen reader skips the image or reads out the file name, such as “banner_final_v3.jpg”.

When email programs block images from loading

Images in bulk emails are not attachments. They sit on a server, and the email program downloads them only when the message is opened. This download is exactly what programs can block, because images can tell the sender that you opened the email. Microsoft gives this as the main reason why Outlook does not download images by default.

So the alt text will be seen instead of the image by:

• recipients in classic Outlook for Windows and Thunderbird who have not downloaded the images manually,
• people who have turned off image downloads themselves, for example in Gmail or Apple Mail,
• recipients of messages that Gmail considers suspicious or of messages in the Yahoo Mail spam folder,
• recipients on a slow connection or behind a company filter that strips images,
• everyone who listens to the email through a screen reader.

How many people that is depends on who you send to. According to Litmus, which measures email opens, the market share of email programs looks like this:

Worldwide, Outlook accounts for just under 6% of opens. But Litmus mostly measures consumer email. If you send to businesses, Outlook is much stronger in your database. We know from experience that desktop Outlook in companies routinely does not download images.

Which email programs block images

Most of today's email programs load images automatically. The exceptions are classic Outlook for Windows and Thunderbird, which block them by default.

Source: Microsoft, Block or unblock automatic picture downloads in classic Outlook and How do I display external images in emails; Microsoft 365 Roadmap; Google, Turn images on or off in Gmail; Apple, Mail Privacy Protection; Mozilla, Remote Content in Messages; Yahoo Help, Block images in Yahoo Mail. Status as of October 2026.

Tip: Mail Privacy Protection on Apple devices downloads images automatically even for emails the recipient never opens. That is why open rates tend to be inflated. More on this in Email open rate: is 20 % a lot or a little?

Styled alt text: a headline instead of an image

Styled alt text turns the empty space left by an image into a headline. Here is a simple test email with a photo of a spring meadow. This is how a recipient whose images loaded sees it:

And this is how a recipient with blocked images sees it. Instead of the photo, they see the bold green headline “Jarní slunce v přírodě” (Spring sun in nature), which we set as the styled alt text:

In Gmail, an email with images not loaded looks similar. There is an “Images are not displayed” bar above the message and the same green headline in place of the photo:

Instead of the image, the recipient reads the information the image carried or a prompt to download the images. The email looks tidy even though nothing in it has loaded.

Where styled alt text is shown: a big comparison

Styled alt text is shown by most webmail services and mobile apps, Apple Mail and Thunderbird. It is not shown by classic Outlook for Windows, which displays alt text only as plain text. Below are three separate tables: webmail, desktop programs and mobile apps. In each you can see whether the program shows the alt text and whether it also shows its styling, that is a headline instead of the image. Which programs block images in the first place is shown in the table above.

What the coverage of styled alt text is

The coverage of styled alt text is the share of email opens in programs that show styled alt text. We calculated it from the email program market shares reported by Litmus and from the tables below.

So roughly nine opens out of ten happen in a program that shows styled alt text as a headline. The figure is indicative: Apple's share is inflated by Mail Privacy Protection, which downloads images automatically, and Outlook's share is higher in business databases. If you mainly send to businesses, expect some recipients to see only plain alt text in Outlook.

Webmail

Webmail services are email programs you do not install on your computer and sign in to through a web browser. Almost all of them show styled alt text.

Desktop programs

Desktop programs are email programs installed on Windows or a Mac. This is where the picture is most mixed: Apple Mail and Thunderbird show styled alt text, classic Outlook for Windows does not.

Historical data from the 2016 Litmus test for programs that are rarely used today: Lotus Notes 8.5 showed alt text without styling, Windows 10 Mail did not show it at all and AOL Mail in Internet Explorer showed it without styling.

Mobile apps

Mobile apps are email programs on phones and tablets, where most emails are opened today. Almost all of them show styled alt text, the exception being Yahoo Mail for Android.

Source for all three tables: Litmus, The Ultimate Guide to Styled ALT Text in Email (2016), supplemented by Quanda's own tests from 2020 in Seznam.cz, Thunderbird, Gmail and Outlook from Microsoft 365.

Good to know about the tables:

• The data comes from tests, not documentation. Email program vendors do not document support for styled alt text. The tables are based on the Litmus test from 2016 and our tests from 2020. The programs have been updated since, so always test your email yourself.
• Not every style works everywhere. According to Litmus, text colour is supported by almost all programs that show styled alt text. Font, size and bold behave less consistently, and some programs apply only part of the settings.
• The text has to fit in the image area. Alt text is shown where the image would be. When it is longer or taller than the image area, some programs cut it off or do not show it at all. With a large font, use fewer words.
• The browser matters too. In webmail, the same mailbox can show alt text differently in different browsers, as GMX and Web.de show.
• Where images are blocked most, styling does not work. Classic Outlook for Windows blocks images and does not show styled alt text. Filled in alt text still helps there, because the recipient reads it in the notice.

The catch: styled alt text in Outlook

Classic Outlook for Windows does show alt text, but only as another unformatted line at the end of the notice that it blocked the image download. It ignores the font, size and colour you set:

Litmus described the same behaviour in Outlook 2003 to 2016, and in our test Outlook from Microsoft 365 behaved the same way. This leads to two practical rules:

1. Put the important words at the start of the alt text. In Outlook they appear only after the notice, so they have to make sense without styling.
2. Do not rely on alt text to rescue an email made of images. Write the main message, price and call to action as text.

Most recipients, however, open emails in Apple Mail and Gmail, where styled alt text works. That is why it is worth setting up, even if Outlook does not show all of it.

How to set up and style image alt text in Quanda

In Quanda, you fill in and style alt text in the email editor for each image separately. Filling it in ensures the recipient sees text instead of the image. Styling it ensures that text looks like a headline. It takes a few minutes.

1. In the email editor, click the image you want to add alt text to.
2. In the right panel, fill in the Image title field with a short text that carries the image's message.
3. Turn on the Set appearance switch.
4. Choose the font, size, colour, style (bold or italics), line spacing and alignment so that the text looks like a headline of the email.
5. To check it, cut the image address from the Insert image address from the web field with Ctrl+X. The editor shows the styled alt text instead of the image. Then paste the address back with Ctrl+V.
6. Send yourself a test email to classic Outlook or Thunderbird and do not download the images. In Gmail, turn on the setting that asks before displaying external images for the test.

How to work with images and other content elements in the email editor is described in the help article Email editor of a simple email campaign.

When styling, keep three things in mind:

• Colour. Without the image, the text sits directly on the background colour of the row or email. Choose a colour that is easy to read on it, ideally the colour of your email's headings.
• Size. A large font looks like a headline but takes up more space. The text has to fit in the image area, otherwise some programs cut it off.
• Font. Use a common font available on computers and phones, such as Arial. A program replaces an unusual font with its default.

How to prepare the images themselves is covered in How to crop an image to a specific size and JPG, PNG or GIF?

How to write alt text that works as a headline

Good alt text says the same thing as the image, only in words. It does not describe what the image looks like but what it communicates. The WCAG accessibility guidelines put it this way: the text alternative must serve the same purpose as the image.

Follow these principles when writing:

• Keep it short. One sentence or phrase, usually up to 100 characters. Styled alt text in a large font has to fit in the image area.
• Write it as a headline. For the main image of the email, write alt text that works as a title: what you are offering and why to read on.
• No filler words. Do not start with “Image of …” or “Photo of …”, the screen reader announces that it is an image.
• For buttons and links, the action. Someone who cannot see the image needs to know what happens after the click.
• Copy the text from the image. If the image contains a written message, all of it belongs in the alt text.

Tip: For an image the email makes no sense without, such as an infographic, the alt text can prompt the recipient directly: “Infographic: 5 steps to a better newsletter. Display images.”

How to design an email that works without images

Styled alt text is a safety net, not a substitute for content. You can tell an email works without images when, after turning them off, the recipient still knows what you are offering and where to click.

• Write the message as text. Put the headline, price, date and main argument in a text block, not in an image.
• A button as a button. In Quanda, use the Button content element instead of an image of a button. It is always displayed, even without images.
• Beware of a single image email. The SPAM test in Quanda flags an email consisting of a single image and an email with more images than text as common content issues. See the guide Setting up mailing in a simple email campaign.
• A background colour as well as a background image. Not all programs show a background image. So also set a background colour on which the text will be readable. More in Autumn updates in the email editor.

Warning: Look at your test email with images turned off too. An empty space that looks like a handy gap in the email editor can mean a white area with a red cross across half the screen in Outlook.

Checklist: an email ready for blocked images

• Every image that carries a message has its Image title filled in.
• The alt text of the main images has appearance turned on and looks like a headline.
• The alt text is short, fits in the image area and has the most important words first.
• The alt text of an image with a link says what happens after the click.
• The colour of the styled alt text is readable on the email background.
• The main message and price are written as text.
• The call to action is a Button content element, not an image.
• You have checked the test email in Outlook or Gmail with images turned off.

Conclusion: the headline works even without photos

Images make an email look nicer, but words carry the message. When you give every image a short alt text and style it as a headline, recipients will understand your message in Gmail, in Apple Mail and in a company Outlook with blocked images.

You will learn how to write and design emails that get read in the online course Email Copywriting and Design That Gets Read. If you are not sure what to do, write to us at support@onquanda.com or call us on +420 605 163 892. We can also go through your email together in a free consultation.

If you have your own experience with styling alt text and how it displays, please share it with us.

Fingers crossed for you
Jan Spáčil