Before you upload images to your emails in SmartrMail, have a read of our image recommendations to ensure your emails look great across all email clients and devices.

General Tips

  • Format
    Save your images in PNG, JPG, or GIF format. PNG images retain transparency and GIFs allow for animations.
  • Color Mode
    Colours used online are different from those used in print, so if you're copying a printed flyer to your email ensure that you change the mode or profile to RGB. CMYK is often used for print, and doesn't render accurately online and can sometimes break uploaded images.
  • Alt Text
    Adding Alt text is needed for accessibility and for users who might not automatically download your images. It also helps email client know the intention of your email, improving deliverability.
  • File Size
    It's recommended to avoid overly large images, both in file size and pixel dimensions. There is a 2MB cap for image uploads to SmartrMail, however you shouldn't exceed 1MB as some images won't automatically download on mobile devices to save subscriber data.
  • Definition
    Retina displays on the lastest smartphones, tablets, and laptops have a higher density of pixels per inch. This can cause some low-resolution images to appear blurred on these high-definition displays. To ensure your images remain clear on all displays save your images at a higher resolution (DPI), but constrain the dimensions based on our image size recommendations.
  • Image Size
    All emails have a limited amount of width for images. These differ based on how many columns your content is in. Read the full section on this below.

Image Size for Emails

SmartrMail emails are 640px wide, so we recommend to size your images based on that maximum.

The number of columns your content is in will also affect the recommended size.

Image Blocks


Not set edge to edge

Set edge to edge

Image + Caption Blocks

If images uploaded exceed the recommended image width's we will resize images within the HTML, but we won't resize the source file to maintain the intended resolution. Not all email clients recognize HTML resizing so we still urge you to follow the recommendations above.

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