No permission required to use. All I ask is common courtesy from others to not claim credit for making them.
To download, click the download button to the top-right of the screen. There will be a zip file which contains varying sizes of this image.
Note: *The 150x150 image is simply a scaled up version of the 75x75 version as working that large of a scale for a portrait is a pain in the ass for me.
More icons like these might be found here: [link]
Reference used: [link]