You have probably heard that images are important for email marketing.
A nice picture can grab attention, make people feel something, and even get them to click a button. Some studies even show that emails with relevant images can get up to 42% more clicks than emails with just text.
But here is the thing. Adding images to your emails is not as simple as just dropping in a photo and hitting send.
Use too many images, and your email might end up in the spam folder. Use the wrong size, and your email will load slowly or look broken on someone’s phone. Skip the alt text, and you are ignoring a whole group of people who cannot see your images.
This guide will walk you through exactly how many images to use, what size they should be, and all the other best practices you need to know. No complicated jargon. Just simple, practical advice that works.
Why Images Matter in Email Marketing
Before we get into the technical details, let us talk about why images are worth your time.
Images stop the scroll. When someone opens your email, they are not staring at it with full attention. They are probably glancing at it while doing something else. A strong image can make them pause and actually read what you have to say.
Images also help people understand your message faster. A picture of a product or a simple graphic explaining an idea can communicate in seconds what might take several paragraphs to explain.
And images build brand recognition. When you use consistent colors, fonts, and styles in your images, people start to recognize your brand without even reading your name.
But like many good things, images work best in moderation. Too much of a good thing can ruin your email campaign.
How Many Images Should You Use in an Email?
This is one of the most common questions people ask. And the answer is simpler than you might think.
Stick to one to three images per email.
That is the sweet spot. Emails with one to three images tend to get the best engagement. More than that, and you start to run into problems.
Here is why. First, more images mean a larger email file size. Larger emails take longer to load, especially on mobile phones or slower internet connections. If your email takes too long to load, people will just close it and move on.
Second, too many images can distract from your main message. If you have five different pictures competing for attention, your reader might not know what you actually want them to do. Are you trying to sell something? Share a story? Get them to click a link? Too many visuals can confuse that message.
Third, image-heavy emails are more likely to trigger spam filters. Internet service providers look at the ratio of text to images in your email. If there is too much image and not enough text, they might flag your message as spam.
If you absolutely need to use more than three images, consider spreading them out across multiple emails in a sequence rather than cramming them all into one.
What Size Should Your Images Be?
Now let us talk about dimensions and file sizes. This is where a lot of people get confused, but it is actually quite straightforward.
Width
For most email clients, the recommended maximum width for images is 600 pixels. This size fits nicely into standard email templates and looks good on both desktop and mobile screens.
Some experts suggest going up to 800 pixels or even 1,200 pixels, but 600 pixels is a safe, reliable choice that works across almost every email client.
If you want a really sharp image on high-resolution screens, you can use an image that is 1.5 to 2 times wider, like 900 to 1,200 pixels, and then let your email platform resize it down to 600 pixels. This gives you a crisp, clear image without breaking the layout.
For square images, 250 by 250 or 300 by 300 pixels works well. For banner images at the top of your email, 600 pixels wide by about 150 pixels high is a good starting point.
Height
Height is more flexible. There is no strict rule, but keep in mind that very tall images can cause a lot of scrolling. Some email clients, like Outlook, may even crop images that are more than 1,728 pixels tall. As a general guideline, try to keep your images under 1,000 pixels in height unless you have a good reason to go taller.
File Size
File size is just as important as dimensions. Large image files take longer to load, and slow loading means less engagement.
Most experts recommend keeping individual image files under 200 kilobytes. For the best performance, aim for under 100 kilobytes. Some platforms even suggest going as low as 20 kilobytes per image.
If your images are larger than that, you need to compress them. There are many free tools online that can reduce file size without noticeably hurting image quality. Most email platforms also have built-in image compression features.
The Text-to-Image Ratio You Need to Know
This is one of the most important concepts in email image best practices. And it is simple.
Aim for about 60% text and 40% images in your email.
That means for every 100 square pixels of your email content, roughly 60 should be text and 40 should be images. This ratio helps your emails stay out of spam folders while still looking visually appealing.
Why does this matter? Spam filters look at the balance between text and images. If an email is mostly images with very little text, it looks like something a spammer would send. Email providers like Gmail are known to be particularly strict about this.
Some sources suggest a more conservative 70% text to 30% images. Others say 80% text to 20% images. The exact number is less important than the general principle: make sure your email has more text than images.
If you are sending an image-heavy email, like a product catalog, consider adding more descriptive text around the images to balance things out.
Which Image Format Should You Use?
Not all image formats are created equal. Here is a quick guide.
JPEG is the most common format. It works well for photographs and complex images with lots of colors. JPEG files are relatively small, which means faster loading times.
PNG is best for images with text, infographics, charts, or anything that needs to stay sharp. PNGs support transparency, but they tend to have larger file sizes than JPEGs.
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GIF is used for simple animations or basic graphics. GIFs have small file sizes but are limited to 256 colors, so they are not good for photographs.
For most emails, JPEG is the safest choice. It gives you good quality with a small file size. If you are using a PNG and the file is too large, try converting it to JPEG.
Alt Text: The Overlooked Essential
Alt text is the description that appears when an image does not load. It is also what screen readers use to describe images to people with visual impairments.
Every image in your email should have alt text.
Here is how to write good alt text. Keep it short but descriptive. Describe what the image shows or what purpose it serves. Do not start with phrases like “image of” because screen readers already announce that it is an image.
If your image has text in it, include that text in your alt description. If an image is purely decorative and does not add any information, you can use empty alt text, which tells screen readers to skip it.
For images that are also links, describe where the link goes. For example, instead of just saying “click here,” say something like “Shop our new collection”.
Alt text is not just for accessibility. It also helps when images are blocked by email clients or slow internet connections. Many people have images turned off by default in their email settings. Good alt text ensures those people still understand your message.
Additional Best Practices for Email Images
Here are a few more tips to keep in mind.
Keep your images relevant. Do not use a picture just because it looks nice. Every image should support your message and help your reader understand what you are trying to say.
Maintain brand consistency. Use images that match your brand’s style, colors, and tone. If your brand is professional, use professional images. If it is casual and fun, use casual images.
Test on mobile. More than half of all emails are read on mobile devices. Always preview your email on a phone before sending to make sure your images look good on a small screen.
Use live text instead of text on images. If you need text overlaid on an image, add that text within your email platform rather than typing it directly onto the image. This keeps the text legible when the image is scaled down on mobile.
Host your images externally. Most email platforms host your images on their servers and link to them in your email. This keeps your email file size small and improves deliverability. Do not attach images directly to your email.
How MailDrip Makes Image Management Simple
At MailDrip, we believe that email marketing should help you grow your business, not get in your way. Too many platforms make simple things complicated. Adding an image should take seconds, not hours.
We built MailDrip with a clean, distraction-free interface that lets you focus on your message. Our templates are designed to work perfectly with standard image sizes, so you do not have to worry about broken layouts.
And our drag-and-drop editor makes it easy to add, resize, and position images without any technical skills.
Our free plan gives you 1,000 free emails and unlimited contacts, so you can start testing your image strategy without spending a dime. And our Pay As You Go option means you only pay when you actually send emails. No forced monthly commitments.
Whether you are a creator, a solopreneur, or a small business owner, MailDrip is built for people who just want things to work.
Frequently Asked Questions
How many images should I put in a promotional email?
One to three images is the sweet spot. A hero image at the top, maybe a product shot in the middle, and a small image near your call-to-action button. Any more than that and you risk distracting your reader or triggering spam filters.
What happens if my image file is too large?
Large images take longer to load, which means people might close your email before it fully appears. Slow loading also hurts engagement over time, and lower engagement can eventually hurt your deliverability. Always compress your images before adding them to an email.
Can I send an email with only images and no text?
You should avoid this. Image-only emails are very likely to be flagged as spam. They also do not work well for people using screen readers or those who have images turned off. Always include some text in your emails.
What is the best image width for email?
600 pixels is the standard recommendation. It works across most email clients and looks good on both desktop and mobile.
Do I really need alt text for every image?
Yes. Alt text is essential for accessibility. It also helps when images do not load properly. Every image should have alt text, even if it is just a simple description.
Will using too many images get my email marked as spam?
It can. Spam filters look at the ratio of text to images. If your email is mostly images with very little text, it is more likely to be flagged. Aim for at least 60% text and no more than 40% images.
What image format should I use for product photos?
JPEG is usually the best choice for photographs. It gives you good quality with a smaller file size. For images with text or sharp lines, like infographics, use PNG.
Your Turn to Start
Images can make your emails more engaging, more memorable, and more effective. But only if you use them the right way.
Start with one or two images per email. Keep them under 600 pixels wide and under 200 kilobytes in file size. Add descriptive alt text for every image. And make sure your email has more text than images.
These are simple steps. But they make a big difference. Your emails will load faster, reach more inboxes, and connect better with your audience.
What is one change you can make to your email images this week?
