Does anyone know where these images originated from?

I’d like to use these images that are scattered all over the internet on my website, but I don’t know who the rights holder is. Also I want one for YouTube, but I can’t find one. ><
Here are some examples:

http://wannabefilm.com/wp-content/uploads/2011/04/112217-glowing-green-neon-icon-social-media-logos-rss-cube.png

http://mywordpresstutorial.com/wp-content/uploads/2010/08/yahoo-logo-square-neon-webtreatsetc.png

http://mywordpresstutorial.com/wp-content/uploads/2010/08/yahoo-buzz-logo-square2-neon-webtreatsetc.png

http://www.google.com/search?hl=en&sa=N&rlz=1C1GGGE_enUS417US437&tbs=simg:CAESYxphCxCo1NgEGgIIBAwLELCMpwgaOgo4CAESEs0G1AbOBssGpwfMBtUGqAemBxogi89PKLuZmpl3mlnZb0lKvPhVdXcFxZhqmWepeIeoIGgMCxCOrv4IGgoKCAgBEgSuSLEgDA&q=logo+facebook+neon&tbm=isch&ei=L4hGT-BW7YHRAb3O7YAO&ved=0CC8Qsw4&biw=1366&bih=624

http://www.useful-free-stuff.com/free-icons?action=view&name=glowing-green-neon-icon-media-full-set

Light and Love!
Joe*