How is it possible to drag & drop photos into another program with the mouse?

How is it possible to drag & drop photos into another program with the mouse?

You can also drag and drop up to 10 photos at a time into an image editing program using the mouse, provided the other application also supports this.
Please hold down the CTRL key (or CMD key on the Mac) before dragging the images with the mouse. Release the key on the keyboard before releasing the mouse button.