png 1x1 gen

demo https://codepen.io/gnjo/pen/pozgqeN
demo https://codepen.io/gnjo/pen/ZEzQmvG

function p1x1(c,w,h){
 //ex) red or #f00 or #f005 or #ff0000 or #00000000 or transparent
 let canvas=document.createElement('canvas'),ctx=canvas.getContext('2d')
 ;
 canvas.width=w||1
 canvas.height=h||1
 ctx.fillStyle=c||"#000000"
 ctx.fillRect(0,0,canvas.width,canvas.height)
 ;
 return canvas.toDataURL("image/png") //output
}