1. A computer-implemented method comprising: obtaining, by a computing system, data corresponding to a first content item; causing, by the computing system, the first content item to be rendered for display; presenting, by the computing system, the first content item through a display interface; capturing, by the computing system, a screenshot image of the display interface while the first content item is being presented; and determining, by the computing system, whether the first content item was incompletely rendered based at least in part on the screenshot image, the determining comprising: identifying, by the computing system, a largest region in the screenshot image including only pixels of a certain color; and determining, by the computing system, that the first content item was incompletely rendered based at least in part on a size of the largest region.