Understanding the Impact of Email Image Blocking

A big part of the internet and digital communications today is visual — there are more images, infographics, designs, and videos than ever before. Websites are vibrant, social media is dynamic, and interactive content is everywhere — modern marketing is all about eye-catching elements.

In an age like this, why do email clients block images? Why is it that an otherwise beautiful email shows as a text and HTML skeleton to your viewers?

Today, we explore the origin story of image blocking, both on emails and websites, and offer ways to quickly resolve this pesky problem!

What is Email Image Blocking?

Image blocking in email refers to the practice of preventing images from loading automatically when you open an email. Many email clients and webmail services enable this feature by default as a security measure. The primary reason for blocked images is to protect users from potential security risks associated with loading external content.

While email image blocking safeguards users from malicious code and tracking pixels, it also poses challenges for marketers seeking to deliver visually compelling content directly to their audience’s inboxes.

Images in Emails: Is Blocking Required?

Many mailbox providers block images by default, but notable exceptions include Gmail and Apple Mail. If either of these two top-tier mailboxes considers the email to be suspicious, the message moves to the spam folder.

For other mailboxes, like Outlook or Thunderbird, things are not as straightforward. These providers have a blanket view of tracking and use image blocking to prevent the loading of tracking pixels. By disabling images, it becomes difficult for senders to track whether an email has been opened. Mailbox providers see this as a privacy feature their users would appreciate.

That’s why the images embedded in the email are not loaded automatically when a recipient receives an email, especially from an unknown or untrusted source. The recipient has the option to choose whether to display the images or not. This is often done by clicking on a button or link within the email that says something like “Load Images” or “Display Images.” If the recipient trusts the sender and is confident that the email is safe, they can choose to load the images.

Image blocking also helps protect user privacy. Loading images in emails can reveal information about the recipient, such as their IP address, location, and the fact that they opened the email.

Email users can choose to block images in emails manually; if they are on slow or metered internet connections, this tiny action can help conserve bandwidth and improve loading time.

Below is a handy table highlighting which mailbox providers block images by default.

Email Provider	Loads image by default?	Displays alt text?
Gmail	✅	✅
Outlook	❌	✅
Yahoo! Mail	❌	✅
Apple Mail	✅	✅
Office 365	❌	✅
Thunderbird	❌	✅

Email Clients: Which ones block email images?

The steps to unblock images in an email can vary depending on the email service the recipient uses. For example, the Outlook app blocks all images, whereas Gmail unblocks images for all emails unless they’re marked as spam.

Below, we’ve listed general instructions to allow images on commonly used mailbox providers.

How to Unblock Images in Gmail

If the images on an email are not visible on Gmail, it’s because the email has been identified as spam. We recommend clicking on the “Not spam” or “Report not spam” buttons, which are visible once the email opens, instead of unblocking all images. But if images are not visible even for the emails in the inbox, here are the steps to fix that.

On Gmail (Web)

Here’s how to resolve the blocked images issue in Gmail on the Web.

Open Gmail on a browser.
In the top-right corner, click on the gear icon to open the Quick Settings pane.
In this pane, click on “See all settings” at the top.
The full-fledged Settings window page should now be visible.
Here, locate the option named “Images.”
There are two radio buttons next to it, offering the options “Always display external images” and “Ask before displaying external images.”
Clicking on the first option will unblock all images.

Go back to the inbox and check if the images are now visible in emails.

Gmail on Android

If images aren’t visible when using the Gmail app on an Android phone, here are the steps to resolve that.

Note that the steps may be slightly different depending on the version of Android, but these steps are close enough.

Open the Gmail app.
Click the hamburger menu — that’s the icon with three lines — on the left side of the search bar at the top.
Scroll down the newly-opened left pane and click on “Settings.”
In the Settings window, click on the Google account — it should show as yourname@gmail.com.
Scroll all the way to the bottom and click on “Images.”
A pop-up window offers two choices: “Always display external images” and “Ask before displaying external images (also disables dynamic email).”
Choose “Always display external images.”

That’s it! Now go back to the inbox, and the images in emails will display correctly.

Gmail on iPadOS and iOS

To disable image blocking on Gmail running on an iPad or iPhone, follow these steps.

Open the Gmail app on the iPhone/iPad.
Click on the triple-line icon at the top, on the left side of the search bar.
In the pane that appears, scroll to the bottom and click “Settings.”
Under the Inbox section of Settings, click on “Email preferences.”
On the next page, click on “Images.”
There is now the option to pick between “Always display external images” and “Ask before displaying external images (also disables dynamic email).”
Pick the top option, and click “Done” in the top-right corner.

The inbox will appear once more. Open an email to verify if images are visible.

Outlook: How to Unblock Images

As Outlook blocks all images by default, it can be a bit of a nuisance for recipients.

These are the steps to disable image blocking on the Outlook app.

Open Outlook.
Open an email where the images are blocked.
There should be two options above the content of the email — “Download external images” and “Go to settings.” Click on “Go to settings.”
If these two options are not visible at the top of the email, in the taskbar, click on Microsoft Outlook > Settings. On a Windows computer, click on File > Settings.
In the Settings window, click on “Reading.”
In the Reading menu, locate “Download external images” and click on the drop-down list.
Select “Automatically.”

Outlook will now display all images inside emails!

How to Unblock Images on Thunderbird

Unblocking images on Mozilla’s Thunderbird email client is similar to Outlook.

Thunderbird chooses to block images by default, and if this bothers you, here are the steps to fix it.

Open the Thunderbird app.
The first way to access the Settings page is to open an email and look for the yellow header that says remote images are disabled. There is a “Preferences” option on this yellow banner; go ahead and click that.
Click on “Edit remote control preferences.”
The second method to reach the Settings page is by clicking on Thunderbird > Settings on Mac or File > Settings on a Windows machine.
Once the Settings page appears, click on “Privacy & Security” on the left pane.
On the right side, under “Mail Content,” there is a checkbox that says “Allow remote content in messages.” Check the box to allow images in your emails.

For many web-based email services, such as Gmail, Yahoo Mail, and Outlook on the web, the process is often similar to the instructions mentioned above. Look for a message at the top of the email indicating that images are blocked, and there should be an option to load or display them.

Remember that unblocking images in emails may expose recipients to potential security risks if the email is from an unknown or untrusted source. Email users must be cautious and ensure that the email is from a legitimate sender before allowing images to load.

Why are Your Marketing Emails Getting Blocked?

Images in your marketing emails may be blocked for several reasons.

Before we tell you how to tackle that, let’s examine the most common reasons your images are causing you trouble.

Client settings: Select email clients, by default, block images for security and privacy reasons. Recipients will need to click a “Load Images” button to display the images in your email. This is a common practice to prevent the automatic loading of images from unknown or potentially malicious sources.
Spam filters: Images in emails can trigger spam filters, especially if they are large, hosted on suspicious domains, or have characteristics commonly associated with spam. Including too many images without sufficient text content can also raise red flags.
Image hosting issues: If you host your images on a server with a poor reputation, email clients may block them.
Incorrect image URLs: If the URLs linking to your images are broken or incorrectly formatted, email clients won’t be able to load the images.
HTTPS Issues: A few email clients may block images that are not served over a secure (HTTPS) connection.
Image size/format: Extremely large images can take a long time to load, and email clients may block them to improve the user experience. Optimized and common formats like JPEG or PNG don’t face such issues.
Alt text missing: If your images lack alternative text (alt text), it may affect accessibility, and email clients might block the images. Alt text is also essential for recipients who have disabled image loading.

So now you have an idea of what’s causing your images to get blocked. Wondering how to fix it? We address this in the next section.

Blocked Images in Emails: What Marketers Can Do

Below are several suggestions to help you tackle the issue of blocked images in your marketing emails. Go through the steps individually and test your emails to check if the issue permits.

Remember, many email clients leave image blocking on, so it may be an issue you can’t resolve on your end.

Reduce the file size of your images to improve loading times. Large images can be slow to load and may trigger image-blocking features.
Descriptive alt text is your friend. Alt text not only improves accessibility but also provides context when images are blocked or not displayed.
Host your images on a reliable and reputable server. Avoid using free or suspicious image hosting services, as this can lead to images being flagged.
Use image caching techniques to improve load times for repeat recipients. This can enhance the user experience and reduce the chances of images being blocked.
Embed important information as HTML text rather than within images. This ensures that even if images are blocked, your core message is still conveyed.
Test your emails across various email clients to identify specific issues with image rendering. Different email clients may handle images differently, and testing helps you optimize for each.
Use secure (HTTPS) URLs for your images.
Ensure that the URLs linking to your images are correctly formatted.
Design emails that are not solely reliant on images. Include essential information as text so that even if images are blocked, the main message is still communicated.
Get SPF, DKIM, and DMARC security protocols on your domain, as they have positive effects on your sender score. Did you know we require all Campaign Refinery clients to implement these three by default?

By implementing these suggestions, you can enhance your deliverability and ensure the visibility of images in your marketing emails while maintaining a positive user experience for your recipients.

Blocked Images on Websites

“Blocked images” generally refer to instances where images on a website are prevented from loading or displaying properly. These situations can be due to various reasons, and they may be intentional or arise from issues with the browser, network, or the website itself. Imagine a scenario where you send an email out with a link to your website, but your recipient can’t view images on the landing page — this can be a huge turn-off and make them exit. Let’s review the biggest causes of blocked images.

The top cause for image blocking is browser settings, where users might unintentionally enable features that block images to save bandwidth or enhance page loading speed. Ad-blocking browser extensions or software can also contribute to blocked images, especially when they identify elements on the page as advertisements.

Additionally, if your website has implemented Content Security Policies (CSP) that restrict the loading of certain content types, including images, for security reasons, images will be blocked. SSL/HTTPS issues, network problems, browser extensions, JavaScript errors, and website technical issues can further contribute to images not loading as intended.

To address these issues, users can disable ad blockers or extensions, ensure a secure connection, and troubleshoot network problems, with specific solutions varying based on the browser. But the first step would be to disable image blocking in browser settings.

We’ve covered the steps for different browsers in the sections below.

Google Chrome

Use these steps to tackle blocked images when using Google Chrome.

Visit the website where the images are blocked.
Go to Chrome settings — on a Mac, go to Chrome > Settings, and on a Windows computer, go to File > Settings.
In the settings menu, go to Privacy and security > Site settings.
Under “Content,” make sure “Images” is set to “Sites can show images.”
The next step is to clear the browser cache. Do this by going to Settings > Privacy and security > Clear browsing data.
Select “Cached images and files” and click “Clear data.”

Now go back to your browser window and refresh the web page. It should display images correctly.

Mozilla Firefox

Seeing blocked images on Firefox? Here are the steps to fix that.

Open up a new Firefox tab.
In the address bar, type in “about:config”
A warning will appear; choose “Accept the risk and continue.”
Next, a blank page with a search bar at the top will appear.
In the search bar, enter “permissions.default.image”
If the value is anything but “1”, click on the pencil icon at the end of the row, and type in “1.”
Click on the checkmark to save the entry.
The next step is to clear browser data; if corrupt, it can cause image loading issues.
To do this, go to Settings (Firefox > Settings on Mac, File > Settings on Windows).
Click on “Privacy & Security” on the left pane, and scroll down to “Cookies and Site Data.”
Click on “Clear Data.”
Go back to the web page with image issues, and refresh it; images should now be visible. If not, this is probably a website issue.

The process is a bit long-drawn, but this method should fix the issue with image blocking on Firefox.

Safari

On Safari, there isn’t an explicit option to enable images, but try the steps below, as these have worked for some users.

Go to Safari > Settings.
Click on the Privacy tab. Ensure that “Prevent cross-site tracking” is unchecked.
The next step is to clear website data. To do that, click on “History” on the taskbar, and then click “Clear History” at the bottom of that menu.
In the popup window, choose a deletion range from the drop-down list — pick “All History,” then click on “Clear History.”

After these steps, try loading the problematic web page again. If it doesn’t work, restart Safari or try a different browser.

Designing Campaigns With Campaign Refinery

At Campaign Refinery, our view is that simple emails, with little to no images, are ideal — but we do support images as well. And that’s not all, we guide our clients to get the balance just right.

Let’s appreciate the silver lining here — prominent mailbox providers like Gmail and Apple Mail allow images, and that’s a significant portion of most email lists today. While other email clients may make your life a bit tough with email image blocking, your main focus needs to be designing emails well and achieving the best deliverability.

Both of these are Campaign Refinery’s strongest points.

This is because we have focused on sender reputation from day one. Over the past decade, we realized that a strong sender reputation works wonders with deliverability rates; that’s why ours is the best in the business. That is also why we’re super picky about which clients join Campaign Refinery.

As for campaigns, our libraries have you covered: we have modern, stylish, and well-balanced templates that will ensure you convey your message even when images are blocked. Combined with our simple email editor, you can design the perfect email with just a few clicks. Our campaign library will ensure that you never run out of creative juice; pick one, deploy it, and sit back and enjoy the rewards.

To discover what email excellence feels like, apply to join Campaign Refinery right now.

Understanding the Impact of Email Image Blocking

What is Email Image Blocking?

Images in Emails: Is Blocking Required?