1. A method comprising: obtaining an image for presentation to a user, the image comprising a set of pixels; identifying a portion of the image within a threshold distance from a border of the image and including one or more pixels from the set of pixels; identifying values specifying one or more colors associated with the one or more pixels included in the portion; determining a measure of diversity of color within the portion based on the identified values; determining whether the measure of diversity of color within the portion exceeds a threshold value; and responsive to determining the measure of diversity of color does not exceed the threshold value: identifying, by a digital magazine server, an additional portion of the image within an additional threshold distance from the portion of the image; and storing information indicating the portion of the image does not include content.