The smaller the total email size, the better. Emails with optimized images and fewer content blocks download more quickly and are less likely to be clipped by Gmail. Learn what’s recommended.
TIP: To reduce the dimensions and file size of large images, follow these steps.
Optimal code and image size for email clients
General guidelines
| Individual image file sizes | Aim for no larger than 200 KB each |
| Animations and large hero images | Aim for no larger than 1 MB |
| HTML code | Aim for no larger than 125 KB |
When an email client receives your HTML email, typically you will see the email load in two phases: HTML first, images second. The total size of the HTML and images combined results in how fast the email will be processed by the email client and on your device. In addition to helping your email load time, there are a few reasons why it is important to keep the total size of your email as low as possible.
Truncating
Many email clients (especially mobile) truncate the email, cutting it off halfway through. You will see a “Download More” button in many cases.
Deliverability
ISPs may block or “hold” large HTML emails for further examination. Large emails can be a sign of spam or an email carrying a virus or malware.
Example of a bounce back message indicating email is too large…
"Exceeded maximum inbound message size"
Mobile load time
With mobile opens between 60-70% it is more important than ever that your emails are as light as possible. Large images will download slowly and could even crash the email application on a mobile device.
Manage the size of your email
The following tips will help you manage the size of your email, improve user experience and engagement, as well as inbox deliverability.
Create lighter emails using emails with fewer columns, concise text, and linking off to your website for additional information. Reduce the number and overall weight of images as much as possible. When choosing your image formats, consider your options.
| GIF |
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| JPG |
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| PNG |
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Optimize your images
To reduce the file size of large, non-animated images
- In the email editor, click an image
- From the left panel, click Edit Image to open the image editor
- Large high-res images will automatically scale down to smaller dimensions (displays in lower-left corner)
- Click on the image to activate the Save and Close button
- Click Save and Close. The optimized version of your image will be saved and added to the email.
In the image editor, you can click the gear icon to access additional settings. You can set the compression levels for JPG and preview the image quality before you save it to your email.
Find the size of your email
You can find the size of your email in most email clients. But you can also do this in your browser.
To find the size of your email using a browser
- Load the View in Browser link from your email in Chrome
- Right-click on the email and select Inspect
- Select the Network tab from the inspector tools
- Reload the email in the browser tab. The Total weight – Code + Images in KB will appear at the bottom of the Network information
To find the email code size in Outlook
- Open the email you wish to review by double clicking on it. This should open it in a separate window.
- Click File on the top left corner, and then click the Info section.
- You will see a section titled Properties on the right. The email code size will be listed under Properties. This is the size of your email code, excluding images.