The images displayed in the thumbnail panel include indicators in the top right corner. These indicators are used to inform the user of the viewing status. There are three unique indicators:
A red dot or circle indicates one or more images in that series have not been fully rendered in the viewer.
A solid red dot indicates the series has not been loaded into an image frame.
A red circle indicates the current image has been displayed, but other images in the series have not been fully rendered in an image frame.