GlobalEventHandlers.onloadstart

img.onloadstart = funcRef;

<img src="myImage.jpg" />

// 'loadstart' est lancé le premier, puis 'load', puis 'loadend'
image.addEventListener("load", function (e) {
  console.log("Image loaded");
});
image.addEventListener("loadstart", function (e) {
  console.log("Image load started");
});
image.addEventListener("loadend", function (e) {
  console.log("Image load finished");
});