If you wish to request thumbnails via API, you've got a couple options:
1) You can request the thumbnail via timestamp (in seconds or percentage rate)
2) Want to request thumbnails at specific intervals? Use !5, for example, to request thumbnails at 5 second intervals
Please note:
– If your specified thumbnail width and height are different from your video's aspect ratio, you may get black spaces added to the thumbnail image.
– If you specify only width or height, the other will be calculated according to your video size.
– If both width and height are not specified, the thumbnail will result in the same size as your video.
– JPEG is the only supported image format for thumbnail images.
If you have any questions specific to the formatting of the API request, please browse here:
http://www.encoding.com/api/category/category/complete_api_documentation#thumbnail_features