Image Sizes and Handling

Optimize image quality to help avoid errors with your newsletter

Get your image ready for your newsletter by making sure it has the right height and width, resolution, file size, and file type. This protects the image's quality and prevents errors in the display.

To determine the right settings for your image - or why your image isn't displaying properly - check out the information and general recommendations for each of these factors in greater detail below. 

  • Image size
  • Resolution
  • File size
  • File type

Image size

"Image Size" refers to the dimensions of your image - the image height and width. compresses any image that's over 600 pixels wide, and the image's height is reduced proportionally. This may cause the image to lose quality - leading to grainy, fuzzy, or blurry images. templates are about 600 pixels wide, so if you want an image to span the full width of your email when viewed on a desktop, we recommend using an image that's at least 600-650 pixels wide. Anything smaller could look blurry if resized to fit the email width. 


Our recommendation for square images is 250 x 250 or 300 x 300. For banner images, it is 600 wide by 150 high.


There usually isn't a specific height for banners, however, keep in mind that very large images may cause scrolling, and some clients, like Outlook, may crop images that are more than 1728 pixels in height.


***Outlook Warning***

Outlook doesn't recognize the HTML that constrains images. This means that if you upload an image larger than the recommendations above, it may display at the original size in Outlook. Be sure to resize your images before you upload them to


What is the recommended resolution for my image?

"Resolution" refers to the number of pixels in an image. When you create an image, certain image editing programs allow you to set the resolution.

Whenever possible, we recommend that you save the original design file with a resolution of 72PPI (pixels per inch). 

File Size

While "Image Size" is the height and width of the image, "File Size" is the amount of storage space your image will occupy. Factors like image size and compression will contribute to the file size of your image.

What is the recommended file size for my image?

No larger than 5MB. 

File Type

"File Type" is a name given to a specific kind of file. Some types of images look better when saved as a specific type of file. This chart shows you which file types work best with certain types of images:


What is the recommended file type for my image?
Type Works best with Pros Cons
PNG All Images
  • Best quality, regardless of content
  • Supports full transparency 
  • Great for text 
  • Can fix some distortions caused by other file types
  • Doesn't compress when uploaded
  • Larger file size
  • Photos
  • Small File Size
  • Distorts image to reduce file size 
  • Doesn't work well with text
  • Doesn't support transparency
  • Compresses when uploaded
  • Logos
  • Simple Graphics
  • Low-Resolution Images
  • Small file size
  • Supports basic transparency
  • Doesn't compress when uploaded
  • Limited to 256 colors
  • Images can appear grainy if they use web-unsafe colors