How to create a JavaScript callback for knowing when an image is loaded?

Question

I want to know when an image has finished loading. Is there a way to do it with a callback?

If not, is there a way to do it at all?

Answer 1

Not suitable for 2008 when the question was asked, but these days this works well for me:

async function newImageSrc(src) {
  // Get a reference to the image in whatever way suits.
  let image = document.getElementById('image-id');

  // Update the source.
  img.src = src;

  // Wait for it to load.
  await new Promise((resolve) => { image.onload = resolve; });

  // Done!
  console.log('image loaded! do something...');
}