Colored pixel GIF

pixel.js

function pixelDataURL (r, g, b) {
    return 'data:image/gif;base64,' +
        btoa(
            [71,73,70,56,57,97,1,0,1,0,128,0,0,r,g,b,0,0,0,44,0,0,0,0,1,0,1,0,0,2,2,68,1,0,59]
                .map(c => String.fromCharCode(c))
                .join('')
        )
    ;
}