Thanks guys for helping me. I already did that.. my code:
var canvas = document.getElementById('canvas');
var context = canvas.getContext('2d');
var map = [
['gras1', 'gras2', 'gras1']];
var gras_with_flower = new Image();
gras_with_flower.src = `/dev/tiles/gras_with_flower.jpg`;
var...