Best practices for email images: Sizes, formats & embed

Reading Time: 12 minutes

Including an email image in your marketing material can work wonders on strengthening your brand image and also increase engagement. Good quality images, whether it’s a product picture or more elaborate graphic banner, grabs readers’ attention and nudges them towards conversion. 

That being said, knowing the best practices for email images is crucial to ensuring they’re being displayed the right way. It’s all about what size and format you choose, as well as how you embed it into your email. 

This article explains everything you need to know about how to embed an image in an email, the right image size for an email, and how to use them to promote your brand in the way it deserves to be presented.

Best practices for using images in emails

As you plan your email marketing campaign, you’ll want to familiarize yourself with the best practices for using images in emails. Sticking to them will help you keep your emails looking professional and appealing to the readers. 

Below, we go over the top things you need to know about using images in your emails:

• Ensure image quality: Always use high-resolution images that align with your email’s message. Poor-quality or pixelated visuals can harm credibility, while crisp, clear images increase engagement and create a professional impression.
• Pick an optimal image file size: To optimize load time and deliverability, keep image file sizes under 100KB. Larger images can slow down email load times, leading to frustration and reduced engagement from recipients.
• Use alt text description: Use descriptive and relevant alt text for each image to ensure accessibility for visually impaired users. Alt text also helps in cases where images don’t load properly.
• Optimize email images for all devices: Many people use their phones to read emails, but desktop or tablet users shouldn’t be forgotten too. Ensure you optimize the images in your emails to appear as intended, no matter on which device the recipient views the content. Using responsive email templates will guarantee your emails show up looking their best.
• Always consider the text-to-image ratio: Avoid using too many images compared to text, as this is one of the spam filter triggers. A good rule of thumb is a 60:40 text-to-image ratio. Too many images or too little text may cause your emails to land in a spam folder. 
• Select the right image format: Stick to common image formats like JPEG, PNG, and GIF. JPEGs work well for photos, while PNGs are ideal for images with transparent backgrounds. GIFs can add a fun, interactive element but should be used sparingly.
• Maintain an overall consistency: Each email you send should reflect a cohesive style. While layouts may vary, design elements such as image styles, colors, header sizes, and email fonts should remain consistent to reinforce your brand identity.

What is the best image size for email?

Although the ideal image size for email can vary, there are guidelines to help you keep them looking crisp and clear on any device. You want to choose high-quality images that fit your brand and maintain consistency across the emails you send.

Consider the type of image you’re including in your email. Is the image in square, landscape, or portrait aspect ratio, and is it a product image, header, or infographic? This affects how the image loads and appears on the screen. Here are some general recommendations:

• Full-width header images: Ideal size would be 600-650 pixels wide and 200-300 pixels high. This ensures the image looks great across devices and doesn’t overwhelm the content.
• Smaller in-body or product images: Recommended size would be 300-400 pixels wide and 200-300 pixels high. These images should support your main message without dominating the layout.
• Thumbnail images: Opt for 100-200 pixels wide and 100-200 pixels high for small images or icons. They work well for previews without taking up much space.
• Aspect ratio considerations: Stick to an aspect ratio of 16:9 or 4:3. This will avoid images looking stretched or squished.
• Mobile optimization: Ensure your images scale well for mobile with widths around 320-480 pixels and corresponding heights. This keeps them responsive and user-friendly on small screens.

It might take a few tries to get the size of your email image right, but once you dial it in, you can use the same formula again and again to ensure your email images are appealing and your emails get high engagement rates.

How to embed images to email

So you have your beautiful images ready, now it’s time to actually add them to your email. That’s called embedding and knowing how to do it correctly will save you a headache. Let’s take a look at how to embed images to emails with such popular email providers like Gmail and Outlook, as well as how easy it is with Omnisend’s email builder. 

Embedding email images with Gmail

Follow these steps to embed an image directly into a Gmail email:

1. Go to your Gmail account
2. Click on the Compose button on the upper left side of the screen
3. Click on the Insert Photo button at the bottom of the message window (it looks like a box with hills)
4. From the Insert Photo page, select the photo you want to use by clicking the Upload option or click on Web Address (URL) to use an image from the internet
5. Click on Insert at the bottom of the screen once you have your photo uploaded, making sure you have your cursor in the email where you want your image to appear
6. To resize your image, click on it and use the boxes to shrink or expand it — you can edit the alt text by clicking the option at the bottom of the selected image

Embedding email images with Outlook

Use these steps if you want to embed an email image in an Outlook email:

1. Go to your Outlook email account
2. Click on the New mail option from the left corner
3. Place your cursor in your email where you want your image to appear
4. Click on the Insert button in the toolbar at the top of the new email
5. Choose Pictures from the menu
6. Select photos from This Device, Stock Images, or Online Pictures
7. When you have your image, click Open
8. Resize the image using the boxes in the corners

Embedding email images with Omnisend

Omnisend simplifies embedding images and GIFs in your emails to help streamline your email marketing processes. Here’s how to embed an image or GIF in an email with Omnisend:

1. Go to your Omnisend account, start a new email campaign and select your preferred email template
2. Once you’re in the email builder, click on the Quick add button at the top of your library
3. Drag the Image element to where you want the image or GIF to appear in the email
4. On the right side of the screen, click Select file to choose the GIF or image you want to add
5. Choose to upload an image from your device or get one from the internet using a URL
6. Insert the image and you’re all set

Personalizing images for email marketing

Targeted experiences lead 80% of consumers to consider trying a brand. And, personalization isn’t limited to text. It’s easier than ever to personalize email images for each subscriber using a service like NiftyImages. For example, including the reader’s name gives an email a personal touch they may not expect in marketing content.

Adding names is the simplest way to leverage personalized images, but there’s also room to experiment with a wide range of other strategies. If you’re trying to get readers to visit a physical store, you could send a custom map of the nearest one based on their location.

Another popular option is to advertise specific products based on a recipient’s history with your brand. Product recommendation emails can be triggered by a variety of behaviors.

The message below invites the recipient to view products they may have shown interest in previously. All while suggesting a few alternatives in case they changed their mind.

Omnisend users love how they can automate most of the busy work that goes into creating product recommendations with the Product Recommender feature. Not only that, they can also use Omnisend’s Brand Assets feature to quickly and easily import their brand’s default logos, colors, social links, and fonts into Omnisend.

Once imported, Omnisend will automatically apply your brand assets to your marketing emails, saving you time and effort every time you want to send something beautiful to your customers.

Creating HTML emails with images using email service providers

This article covers only HTML emails that are sent via email service providers for promotional purposes. It aims to answer questions about how to send HTML emails with images and how to embed images in HTML emails.

These emails include: 

• Email layout
• Text formatting
• Coupons
• Images
• Rich media elements

When building a beautiful HTML email, marketers use email service providers such as Omnisend. These platforms have email-building tools — ready-made studios for marketers, so they could quickly design an email and include images they want. 

Usually, these email builders apply a drag-and-drop method as well as WYSIWYG (a.k.a. what you see is what you get). So, you can easily embed your image into the email by simply dragging the necessary content blocks and uploading the image you want.

See below an example of the Omnisend Email Builder:

There are email builders that offer a built-in image editing functionality. These allow you to edit images and adjust them to your email design in the email content editor.

For example, within the Omnisend platform, you can use the Adobe Creative Cloud Connected image editor. On Omnisend, image sizes can be edited this way, too. Since you don’t need to use any other apps for images, building better-looking newsletters becomes a lot quicker.

Using email background images

Most ESPs have the functionality of adding background images to promotional newsletters.

On the one hand, using background images can help your email stand out from other emails. It also gives more email design opportunities.

On the other hand, not all email clients display these backgrounds equally. So, for some recipients, your email can be viewed differently than you initially wanted.

Whether it’s worth using it or not, you can decide after analyzing your audience and its email clients in your Google Analytics account.

Why you should never send image-only emails

Sending emails that only contain images might seem visually appealing, but it comes with significant drawbacks that can harm your email deliverability and user experience.

Deliverability issues

Many email clients are cautious with image-only emails, often flagging them as spam. This is because image-heavy or image-only emails are commonly associated with promotional content, which spam filters are designed to catch. 

As a result, your emails may end up in the spam folder, severely limiting their reach. For better results, it’s crucial to maintain a balance between text and images in your emails. You can read more about email content for better deliverability to ensure your emails land in the inbox.

User experience

Not all users will have images automatically enabled in their email settings. Some email clients block images by default, which means recipients may only see a blank email, so your message gets lost entirely.

Additionally, image-only emails pose accessibility issues for visually impaired users who rely on screen readers. Since these tools can’t interpret images, they won’t be able to convey your message unless alt text is included, and let’s face it — you can’t fit an entire email message just in the alt text. 

A balanced mix of text and images ensures your email is readable and accessible to all users, improving engagement and conversion rates.

Using images to develop a brand voice

As well as personalization, users also look out for brands. They look for consistent identities that align with their core values. When used correctly, images can become a part of your distinctive voice. This requires attention to detail in visual design and a commitment to finding images that illustrate something unique about your brand.

Of course, a brand identity is important for more than just images in email campaigns. A cohesive voice can help you make informed decisions in every area of marketing. Building an engaging and unique tone is much easier once you understand what separates your brand from the competition.

Like personalization, your brand identity should tie to customer research. For example, millennials and Gen Z are looking for something different than, say, parents or retirees. That said, every brand sells to people in different demographics. Your identity should be flexible enough to appeal to a variety of customers.

If you’re primarily targeting younger customers, you might use images that emphasize that your brand is on the cutting edge. On the other hand, brands that focus on parents could look for images that illustrate the benefits of their products for families.

A brand identity is essential and should be clear throughout the entire customer experience, from emails and social media to transactional communication. If two different teams manage your social media and email campaigns, they should be in sync. They should update each other to ensure that both sides are working toward the same goal.

How to find email images

Now that you know how to effectively use images in email marketing, you can start looking for images to integrate into your next campaign. Some images will come with restrictions for certain kinds of use. However, there are a variety of ways to find images that are completely free to use for marketing purposes.

Use stock images

Stock images are the simplest way to add images to your marketing emails, and they’re available on a number of sites. With millions of images at your disposal, you should be able to find exactly what you’re looking for. You can also edit stock images by cropping, adding text, adjusting colors, and more.

People often think of stock photos as generic, but they can also look just as authentic as a picture taken by your team. For example, you could look for a stock image that features a “normal” person rather than a model. The first image below is much more natural than the second, which clearly looks like a stock photo.

There are far too many stock image sites to cover in a single article, but these 21 platforms are an ideal place to start. Remember to double-check that an image is free for commercial use before putting it in an email.

Take your own photos

Stock images are perfect for some occasions, but they aren’t as useful for product launches or other things directly related to your brand. In these cases, it may be easier to take photos in-house, especially as high-quality cameras become more prevalent.

Audiences often look for personal connections. Consider using pictures of people in your organization to introduce readers to your team. Taking photos yourself opens up a variety of engaging opportunities. These aren’t available with other options, such as stock images or AI-generated content.

For beautiful, high-quality images of your products you may want to use a portable photo studio.

Find illustrations

Images are a great way to add some personality to your content, and illustrations give you even more control over the tone of each message. They’re also an effective option for maintaining a consistent voice as you can use the same style and color scheme across multiple emails.

Illustrations are significantly more flexible than their alternatives. They aren’t limited by the possibilities of an actual photo. For example, a drawing could demonstrate different ways to use your product without showing a real person. Illustrations tend to be less distracting than photos, especially when you need to include several images in the same message.

This illustration is a much more natural choice compared to taking photos of people during each step in the buying journey. The main downside of illustrations is the cost of an illustrator — a contractor or freelancer may be more affordable on a short-term basis rather than paying someone in-house.

Use AI technology

Using AI technology in your email marketing campaigns can give you an edge and help you automate your process so you get better results in less time, especially when it comes to images. With AI image tools, you won’t have to spend hours searching through stock photos or other images to find the ideal picture for your email. 

Creating images with AI is pretty simple — you input a description of what you’re looking for, so the app could then generate image options for you to choose from. 

Creating a consistent brand image is another benefit of using AI technology for your email marketing. The AI tools can learn what works best for your brand and keep those details straight, taking the pressure off of you.

Image size for email signature

Since we’re on the topic of images in emails, you may also want to add one to your signature.

Using an image for your email sign-off can give your messages a distinctive flair without distracting from the rest of the content. That said, a signature that’s too large or too small will only look sloppy and unprofessional. Most users read emails on their phone, so images need to be displayed well on all devices.

Email services respond to oversized images in a variety of unpredictable ways. For example, they might shrink the image to the dimensions of the screen. They may also shrink the entire email or expand the message so that users can scroll across the image. With that in mind, your signature needs to fit the dimensions of each screen.

If you want an image in your email signature, try to keep it as small as possible. While there isn’t a strict rule for image size in email signatures, it’s best to use images that are no more than 150 pixels tall and 300 pixels wide.

Remember that file size is just as relevant as the size of the image itself. Large files can take a long time to download, especially on poor connections.