The PSD file is fully layered. All layers are vector based (shape-layers), so a resizing wont affect a quality. You can easy enlarge it or make it smaller and it will be always high quality! The original size of the file is 4000x4000 Pixels.
You can: Easy change color of the snow globe; | Resize it without loosing quality | Place any objects into dome or use ones which already in the file | Use any backgrounds (the dome has its transparency, so it looks nice on any background)