web site blocking screen image retrieval exlampe http://ctrlq.org/screenshots/ http://www.thumbalizr.com/ I want to avoid receiving screen display how do I prevent my site script php
Huh? Could you repeat that in English? I can't figure out if you want to block those types of sites from making screenshots (you can't), block users from hitting print-screen (you can't), or actually want to make screenshots...
You want to block them from making a screenshot of your site? Block their IP address in your .htaccess file.