File size restrictions help to ensure the email is delivered efficiently

Large image files can cause delivery and bandwidth problems for your subscribers. In order to make sure resources are used efficiently and that you do not upload image files that can reduce the effectiveness of your email campaign, the system will analyze the uploaded file and warn you if it is large and prevent you from uploading files that are too large.

One common reason for an image being too large is that its physical dimensions (in pixels) is much larger than it needs to be. For example, you might have an image that is originally 600 pixels wide that displays in the newsletter at only 100 pixels in width. Even though the resulting display is 100 pixels wide, the email program or browser still downloads the 600 pixel wide original image and then scales it down to 100 pixels on the screen.

In this case, shrinking the image first in a paint program, like Photoshop or Paint Shop Pro, to 100 pixels wide can make the image file being used 6 times smaller than the original. This smaller file might go from 60K to 10K in size and should be the version you upload to your newsletter.