Thumbnail images serve as metadata for the applicable article. Based on the size of the device and the available images, your app will automatically choose which image to use in different cases. Currently these images are used as teaser in the various Table of Contents views, e.g. the paginated iPad TOC, the iPhone/Android article list TOC and the iPad side menu list TOC. GTxcel’s conversion process automatically creates the 2-3 auto-cropped versions of the first image from each article. (The landscape image will only be present initially if the conversion process detects an image of the appropriate size and shape.)
Please check to make sure the right representative image for the article is being used. If not you should replace all variations of the image.
If you only want to correct the cropping, e.g. an image of a person is missing key facial features:
you may want to upload a new version of the badly cropped thumbnail.
To update the cropping, you will need to create a re-cropped version with the pixel dimensions below, in JPEG format:
Large Thumbnail: any aspect ratio, with a max of 600 pixel height or width
Landscape Thumbnail: 600×400 pixels. Note that this format is only available for some articles and can not be added if it is not available.
Square Thumbnail: 200×200 pixels
Then click the “REPLACE IMAGES” button to open the upload dialog.