In Photoshop, what is a smart object?
In Photoshop CS2 and above, it has a special layer known as Smart Object Layer. Smart objects give freedom to work with multiple copies of a single object. All the multiple copies will be updated simultaneously when single object is updated. Also, changes in the adjustment of layers and layer styles of a single object can be done without affecting the multiple copies. Without any loss in pixel, pixel based objects can be changed several times.