data-driven insights

Do images send your cold emails to spam? No - we checked!

lemlist team
Last Update
Nov 7, 2023
Reading Time
7 min.

You might have heard that images hurt your cold email deliverability - or that you need a careful 60/40 ratio of text to image to stay out of spam.

Well, we analyzed millions of cold emails to find out if that’s true. Turns out - it isn’t!

Not entirely, at least.

In most cases, images are perfectly safe to include in your cold emails. We’ll dig into the data to explain why and give you tips to improve your overall email deliverability.

Do images reduce email deliverability?

According to our analysis of millions of cold emails sent over a period of one month: no, there is no significant difference in deliverability between emails with and without images. So you can include images in your cold email campaigns without worrying that it will get your message sent to spam.

Let’s dig a little deeper.

To measure the deliverability of emails with or without images, we took a look at their open rates.

Why? Because if your emails are being sent to the spam folder, then your prospects are not opening them.

So if emails with images in the body text get a significantly lower open rate, that’d be a pretty sure sign that they’re getting flagged as spam.

However, when we analyzed millions of emails, there was no difference in open rates between emails with or without images.

Here’s the data:

A bar graph with the title "do images in cold emails hurt your deliverability?" The Y axis shows open rates, and the X axis has 3 bars: with images, no image, all emails. All three bars are around 40% open rates

Note: We did find that the presence of pixel trackers can slightly increase the chance of your emails being sent to spam.

But as long as the rest of your technical setup is okay, and you’re following deliverability best practices, this shouldn’t be an issue for you.

And don’t worry, we’ll tell you more about deliverability best practices later on in this article.

What is the 60/40 ratio for images in cold email?

The 60/40 text-to-image ratio is an old rule of thumb that recommends emails be 60% text and 40% image, or they'll get flagged as spam. It comes from spammers using images instead of text to avoid spam filters. However, studies show that this rule is largely outdated.

According to one study, only emails with 500 characters or less risk landing in spam if the ratio of text to image is off.

If your email is at or above 500 characters, including anywhere from zero to three images will have no positive or negative effect on your deliverability.

If your email is below 500 characters, then adding one image can help it stay out of spam. So, in this case, adding an image to short emails can actually help you avoid spam.

However, adding more than one image to an email under 500 characters doesn’t make any significant change.

In any case, it’s a good rule of thumb to keep your emails at or above 500 characters. According to our data, the sweet spot is right around 120 words (roughly 700+ characters).

A line graph with the title "how long should your cold emails be?" The x axis shows booking rates and the X axis shows number of words. The peak of the line graph is at 120 words

To learn more about the best length and formatting of your cold emails, read this guide on how long your cold emails should be.

Do GIFs in email cause spam?

Including a GIF in your cold email has a slightly higher chance of hurting your email deliverability than including images. That’s because if the file size of your emails is too large, it can trigger spam filters. GIFs have larger file sizes than images and have more of a risk of arriving poorly formatted in your prospects’ inboxes.

To double-check, we ran the same analysis of millions of emails, this time testing if having GIFs in the body text would decrease open rates.

In fact, it does.

Emails with GIFs had a lower open rate on average than emails without GIFs. 👇

A bar graph with the title: Do GIFs in cold email hurt your deliverability? The Y axis shows open rates and the X axis has 3 bars: with GIF, without GIF, all emails. The column with GIF has an average open rate around 36%, and other other emails are at or above 40%.

So avoid adding GIFs to your email campaigns if you’re worried about deliverability.

What can affect email deliverability?

In general, email content has a small effect on your email deliverability. Larger factors like your technical setup and sender reputation have a more important effect on your deliverability than content questions like images or GIFs in your cold emails.

Verify your email technical setup

Your technical setup is what email providers use to verify and validate your sender identity. And to make sure you’re neither a spammer nor a scammer.

So having a complete technical setup is key to staying out of spam.

Your technical setup includes:

❒   SPF: Sender Policy Framework verifies that your emails have been sent from your domain

❒   DKIM: DomainKeys Identified Mail guarantees that your emails are not changed after they are sent

❒   DMARC: Domain-based Message Authentication, Reporting & Conformance helps protect your domain from attacks, phishing emails, etc.

ℹ️  Here's a guide to help set up your SPF, DKIM, DMARC

❒   MX Records: Mail exchange Record helps providers know what servers accept emails for your domain. Without it, you won’t be able to receive emails

ℹ️  Here's a guide to help set up your MX Records

❒   Custom Tracking Domain: Allows you to track open and click rates in your emails safely

ℹ️  Here's a guide to help set up your Custom Tracking Domain

Here’s what those tests look like on the lemwarm warm up and deliverability dashboard

A screenshot of a technical setup dashboard, which includes the status of MX exchanges, SPF record syntax, DMARC record, Email tests, and Spamassassin score.

Protect your sender reputation

Your sender reputation is a score that email providers assign to your domain - the better it is, the more likely you’ll land in the inbox. And the worse it is, the more likely you’ll land in spam.

A variety of factors go into your sender reputation, like if individuals have reported you as spam before, you have a high email bounce rate, or you haven’t warmed up your domain.

A great way to protect yourself from getting flagged as spam and harming your sender reputation is to warm up your domain.

This means gradually increasing your sending volume to avoid triggering email providers. Because if you haven’t been sending emails and suddenly send 100s of emails daily, it can look like spam.

While doing your email warm-up, here are 3 things you should remember:

  • keep your warm-up and deliverability booster ON before, during, and after sending your campaigns
  • wait till your deliverability score is > 90 to send email campaigns
  • always use a safe warm-up tool to protect your sender reputation 👇
A screenshot from the lemwarm deliverability booster tool. There is a meter showing the deliverability score at 99, in green. With the text "you can start your campaigns."

For more information, use this complete checklist to improving your cold email deliverability.

For a tool that will help you avoid spam and reach prospects’ inboxes on autopilot, try boosting your email deliverability with lemwarm.

Should you include images in emails?

Now you know that adding an image or two to your cold email campaign won’t get your messages sent to spam.

But do prospects actually respond to them?

According to our data: yes! Adding images to your cold emails can actually increase your reply rates, compared to emails sent without any images.

Take a look 👇

A line graph with the title "adding an image to your cold emails can boost reply rates." The Y axis shows reply rates, and the X axis shows number of images. The line increases from 35% to 43% at 1 image, then decreases steadily with extra image

The key to adding images in cold emails is to personalize them to your prospects.

75% of people are more likely to buy from someone who recognizes their name, recommends things based on their profile, and knows their history. Plus, 81% of consumers want brands to get to know them.

So when you add images to your campaigns, make them specific to the prospect. You can do that by adding text and image variables to the visual itself.

Take a look at this full breakdown of how to use images in your cold email campaigns.

Key takeaways

To wrap things up, here’s everything to keep in mind about how images in cold emails impact your deliverability:

  1. Including 1-3 images in your cold emails won't impact deliverability, so you can use visuals without ending up spam.
  2. You only need to worry about the text-to-image ratio if your emails are below 500 characters. In that case, try adding one image.
  3. Avoid using GIFs in your cold emails, as they can lower your open rates and potentially trigger spam filters.
  4. For deliverability, focus on your sender reputation and technical setup, including SPF, DKIM, DMARC, and MX Records.
  5. If you do want to use images, go for personalized images, demonstrating that you know your prospects and understand their needs.

P.S. One certain way to keep your emails out of spam is to use a warm-up and deliverability booster. Without one, you’re at a much greater risk of losing credibility and replies.

lemlist team
Your source of actionable outreach tips and strategies that will help you get replies and grow your business.

What you should look at next

Receive weekly outreach tips in your inbox, sent to 210 000+ salespeople, marketers, founders, and entrepreneurs worldwide!

Subscribe to the lemlist newsletter
You've successfully subscribed to the lemlist newsletter!
Oops! Something went wrong while submitting the form.