Explore and download art works, even customizing your lock screen automatically, with City Art Search
City Art Search is a nice, free and powerful app you can use to browse works of art from all over the world according to various filters and criteria.
You can read information on the works, download them, even apply them automatically to your lock screen following some schedule.
Another nice feature is the creation of slideshows. City Art Search is able to display your search results as a slideshow if fullscreen with each slide being displayed for as long as you define.
City Art Search can change automatically the wallpaper of your lock screen with works of art you select, in intervals of 15 minutes or just each day.