When using any of these logo graphics, you will need to open them in an SVG editing program, scale to the pixel size needed, then export that size as a PNG. This way we avoid any issues with pixelization of the images. We recommend Inkscape as a great SVG editor.
When using the logo on a light background, where black would normally be used, use the Official Black Logo
When using the logo on a dark background, where white would normally be used, use the Official Green Logo