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Employee email image size best practices: How to make your messages look great

John Rost

If you’re working with standard tools to send emails to large groups (like employees), figuring out the right image sizes for email and making them render properly to your recipients is a serious challenge. Many mass emails – like marketing emails and customer service messages – are created using a dedicated tool like Mailchimp or Hubspot, but internal communicators are generally left to their own devices in Outlook or Gmail. (That’s why we created Workshop, but if you don’t have an internal email tool yet, keep reading for some other options!) If you’re sending emails to your company, follow these email image size best practices to avoid the dreaded “linked image cannot be displayed.”

How to optimize images for mobile email and desktop email

The biggest hiccup for images in email is file size. No matter how beautiful an email you’ve created, if it doesn’t display properly on your recipients’ phones or desktop, it doesn’t matter. Also, an email with images that aren’t set up correctly might suffer from poor deliverability, which affects all of your other email metrics as well. Watch for these things as you create images to send in an email.

Choosing an image file type  

There are a few different common image file types that you might consider adding to an email – and there isn’t any one single “right” answer. But, if you’re sending images in emails straight through Outlook or Gmail and you’re not getting any help with optimization, every choice counts. Here are the differences between JPEG, PNG, and SVG images, and how they affect your email.

  • JPEG is probably the most common image you see. But JPEGs are pretty limited – they don’t always render properly after compressing and sending through email (sometimes referred to as “lossy”), and they don’t have any transparency.
  • PNG is generally the “graphic designer’s choice” for high-quality image format, for good reason. You can compress and un-compress a PNG without any loss of image quality, and PNG images can be saved with transparency, which gives you more design flexibility. 
  • An SVG is another image file type that designers frequently use, but it’s not usually for photos. The “V” in the name is “vector,” which is usually how line graphics (like your company logo) are exported so that they can be re-sized without getting blurry or pixelated. 

When clicking “save” or requesting images for email from your graphic designers, consider each of these when choosing the file type. 

The best image quality for emails

There are two choices need to make when saving and exporting images for email – quality AKA pixel density, and color values. Pixel density is measured in DPI, and you should see it as an option when you’re saving an image. Make sure your image quality is ready for email by setting your resolution to 72 DPI. This will make sure your pictures aren’t pixelated in mobile email without making them unnecessarily large.

Another choice you’ll see when exporting or saving images for email is color values. Choose RGB every time. CMYK is mostly for print, and will not help your image quality in emails at all.

Choosing image size for email   

When you’re emailing an image, it will always have to be rendered on the other side of the exchange. That’s why considering email size is important (and it’s why every email in Workshop is automatically compressed to be as small as possible).

600px wide is the average size for emails and templates. You can go up to 900 pixels wide if you have a tool to compress the image. An image can go as tall as you like, and will size to the screen of the image viewer, but larger than that width just won’t be necessary. When exporting or saving your images, a good rule of thumb is 2x that size.

Email banner sizes

Most employee emails – especially employee newsletters like those our customers send – look best with a full-width header image. Keep it short (not too tall) so you don’t move your content too far down “below the fold.”

In Workshop, we typically see users create email banner widths 600px to 700px wide, with a height of 90px to 200px. We also recommend exporting and saving your header image at 2x that size to make sure it shows up beautiful and crisp.

Image accessibility in email 

When you start creating beautiful, image-heavy emails for your organization, there is one more thing you need to be aware of… accessibility. Design standards exist to make sure that anyone with visual impairment can get the information they need from your email. Make sure that all images in your email use alt text that describes accurately so a screen reader can interpret them. Also keep a watchful eye on the color contrast in the images you choose – especially if you’re setting your email against a background color.  (Use a contrast checker if you’re not sure!)

Can you send animated GIFs in emails?

Maybe. Probably? GIFs work pretty well in Gmail, and can be hit-or-miss for mass sending in Outlook. If you have your Outlook configured right, and your recipients all do, too, it will work. The safest way to send GIFs, videos, and other rich content and be sure that it’s going to display right is to use a platform built for email creation.

How to compress photos for email

Compressing photos to the best size for email means making your images as small as possible without hurting the quality for recipients on either desktop or mobile. There are different ways to compress images depending on your image platform, but where you really run into image size difficulty is when you’re sending mass emails. If you’re not compressing your images reliably, you’ll be hurting the load speed and deliverability of your emails. There are two ways, basically.

Compressing images for email the hard way

One way is to use an outside tool like TinyPNG. It’s works pretty well, but anytime you’re introducing another step, you’re introducing a lot of complexity into your workflow. 

Another way to compress email images is to use the compressor built into Outlook. It also works adequately, but it only works in Outlook, which leaves you limited to all the ways that Outlook is not good for sending mass internal emails. Here’s how to do it.

Compressing email images the EASY way with Workshop

As part of our recent update to the media library in Workshop, every image sent through the platform is automatically compressed to the smallest possible size without quality loss! The result – emails that send 75% faster (!) with absolutely no loss of quality, and no need to use any additional tools to compress your image files.

Plus, building emails in a platform designed for internal communications emails takes away all of the awkwardness of trying to make those images fit. Workshop customers love building their email brand exactly how they want it using a simple, intuitive drag-and-drop email builder.

If you’re ready to start building, sending, and measuring beautiful employee emails and never worry about email image compression or speed again, check out Workshop!

workshop, the number one platform for employee emails

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