Has Thumbnail: If a thumbnail has been set in the C8 backend to something besides noimage.jpg, it's considered to have a thumbnail.

Has Large Image: If a large image has been set in the C8 backend to something besides noimage.jpg, it's considered to have a large image.

Detected Thumbnail Images: The number of thumbnail images found by the algorithm used to determine applicable images for an item. This is possibly different from the thumbnail set in the C8 backend since it follows a patternized approach based on the item's SKU.

Detected Large Images: The number of large images found by the algorithm used to determine applicable images for an item. An item can utilize multiple large images for displaying representations of attributes. This is possibly different from the large image set in the C8 backend since it follows a patternized approach based on the item's SKU.