According to the https://www.w3.org/TR/2017/REC-html52-20171214/editing.html#the-drag-data-store The display is an optical function:The following information, used to generate the UI feedback during the drag:User-agent-defined default feedback information, known as the drag data store default feedback.Optionally, a bitmap image and the coordinate of a point within that image, known as the drag data store bitmap and drag data store hot spot coordinate.For example, in Chrome and Safari there is no gradient of transparency on MacOS regardless of size.The gradient, who is present on Windows, shows in part the coordinates of the point for which the overstretching occurs.A little information also provides a section https://developer.mozilla.org/en-US/docs/Web/API/HTML_Drag_and_Drop_API/Drag_operations MDN:Setting the drag feedback imageWhen a drag occurs, a translucent image is generated from the drag target (the element the "dragstart" event is fired at). ♪ ♪One way or another, it is not worth relying on this conduct because it is not standardized. In cases where the conduct is relevant, the standard provides for use https://developer.mozilla.org/en-US/docs/Web/API/DataTransfer/setDragImage dataTransfer.setDragImage(element, x, y)Uses the given element to update the drag feedback, replacing any previously specified feedback.The same is recommended by MDN:...you can use setDragImage() to specify a custom drag feedback image.UPD. It's just Windows. All the pictures more than 240 pics on any gradient.
In 2013, this value was https://stackoverflow.com/q/18841228/3344612 ♪Indeed, unfortunately, the pictures delivered through setDragImagetoo. In this case, javascripts should be used to manipulate refinishable objects.