Copy protect images. Insert encrypted images with Domain Lock copy protected from right-click mouse-save, page-save, drag-n-drop and site grabbers.
All popular web browsers are supported on all platforms including Windows, Mac and Linux (100% of net users).
Nothing that will work on all platforms because itís not possible to control capture without using system level plugins and that is only possible on Windows. However if you are happy to provide support for Windows computers only (92% of net users) then there are several more secure options available (safe from Print Screen and screen capture) from ArtistScope that are also available as WordPress plugins.