When Sokar was showing us the editor updates, I suggested a GUI to help set the advanced thumbnail cropping options. (The new fields to set the x/y coordinates for the section of a frame to be used, and the section of the thumbnail for it to be scaled to.) This would help because it is difficult to estimate pixel coordinates without help from an image editor of some sort, and I have seen JS libraries that provide some image cropping abilities in the past.
When Sokar was showing us the editor updates, I suggested a GUI to help set the advanced thumbnail cropping options. (The new fields to set the x/y coordinates for the section of a frame to be used, and the section of the thumbnail for it to be scaled to.) This would help because it is difficult to estimate pixel coordinates without help from an image editor of some sort, and I have seen JS libraries that provide some image cropping abilities in the past.