Issue #2934960 by marcoscano, mycw1991, seanB, evankay, chr.fritsch, andrewmacpherson, jefuri, Jeroen Witte: Clean up icons that ship with Media

Issue #2831937 by mtodor, seanB, Wim Leers, phenaproxima, l0ke, webflo, tedbow, Gábor Hojtsy, slashrsm, naveenvalecha, mondrake, oriol_e9g, dawehner, vijaycs85: Add "Image" MediaSource plugin