People likely create the hotspot graphics on their own using programs like Photoshop. Creating a new static graphic is quite easy while creating an animated graphic would require a bit more work. The easiest approach is to take an existing static or animated graphic that comes with krpano, open in Photoshop (or some other graphic program), then create new designs on another layer while using the original design as a guide. You want the same placement and size as the original. Delete the old graphics/layers then save your new graphic as a PNG-24 using the same name and directory as the original. This approach allows you to get something new without having to edit any code.
If you change the size or desire an animation with more steps, you would also need to alter the associated XML code.