linux.svg / linux.png
Source: https://secure.wikimedia.org/wikipedia/commons/wiki/File:Tux-G2.svg
License: public domain

fedora.svg / fedora.png
Source: https://secure.wikimedia.org/wikipedia/de/w/index.php?title=Datei:Fedora_%28Linux-Distribution%29_logo.svg&filetimestamp=20080912041413
License: registered trademark

xfce.svg / xfce.png
Source: https://secure.wikimedia.org/wikipedia/en/wiki/File:Xfce_logo.svg
License: Creative Commons Attribution-Share Alike 3.0 Unported license

ubuntu.svg / ubuntu.png
Source: https://secure.wikimedia.org/wikipedia/commons/wiki/File:UbuntuCoF.svg
License: registered trademark

suse.svg / suse.png
Source: https://secure.wikimedia.org/wikipedia/en/wiki/File:Suse_logo.svg
License: GPL / registered trademark

redhat.svg / redhat.png
Source: https://secure.wikimedia.org/wikipedia/en/wiki/File:RedHat.svg
License: registered trademark

macos.svg / macos.png
Source: https://secure.wikimedia.org/wikipedia/en/wiki/File:Mac_OS_Logo_with_Text.svg
License: registered trademark

osx.svg / osx.png
Source: https://secure.wikimedia.org/wikipedia/en/wiki/File:OSXLeopard.svg
License: registered trademark

kde.svg / kde.png
Source: https://secure.wikimedia.org/wikipedia/en/wiki/File:KDE_logo.svg
License: registered trademark

gnome.svg / gnome.png
Source: https://secure.wikimedia.org/wikipedia/en/wiki/File:Gnomelogo.svg
License: GPL / registered trademark

gentoo.svg / gentoo.png
Source: https://secure.wikimedia.org/wikipedia/en/wiki/File:Gentoo_Linux_logo_matte.svg
License: Creative Commons Attribution-Share Alike 2.5 Generic / registered trademark

bsd.png
Source: https://secure.wikimedia.org/wikipedia/en/wiki/File:Freebsd_logo.svg
License: registered trademark

windows.png
Source: https://secure.wikimedia.org/wikipedia/en/wiki/File:Windows_logo.svg
License: registered trademark

vmware.svg / vmware.png
Source: https://secure.wikimedia.org/wikipedia/en/wiki/File:Vmware.svg
License: registered trademark