The following are free and downloadable sized watch wallpaper images.
They are all provided under the creative commons zero license which means you are free to reuse in both for business and personal purposes.
There are a variety of Rolex and Breitling watches, as well as a variety of both pocket watches and mix of other watch brands at the end.
If you know of other sources of freely available images that are high quality, please let me know so I can also share them here.
Rolex Watches
Breitling Watches
Pocket Watches
Other Watches
