Requested by: (Note: Hope you don't mind that I used an extra vector in this! If you want me to, I'll take it off!)
Friendly Neighborhood Rainbow Dash vector [link]
Steam Logo: [link]
How to use the icons (Sorry Mac users, I don't know how to change the icons on a Mac!)
1: Click on 'Download' all the way on the right and save the icon.
2: Right click on the program (for this one, Steam) that you're gonna use one of the icons on, then click on 'Properties.'
3: After you've clicked on Properties, click on 'Change Icon,' and then 'Browse' in the next window that pops up, and find where you put the icon file.
4: Then click OK on the window you were on before, and you're done!
Mac Version: [link]