title: How can I read the the dimension of a picture when I open it?
body: <p>I'm making an application that can apply a filter on a picture. I set up the canvas 800 * 500, so when I upload an image bigger, the image is cropped. </p>
  
  <p>How to read the dimension when I upload an image and then set up the dimension of the canvas before to copy the image on the canvas?</p>