Hi, your code does create an instance and attaches it, but there's no reference to use to remove it later. you need to create an attribute, set it to an instance, then attach the attribute.
I've attached a screenshot. Also, i've found that after you remove the image it's good to use the code block with _yourImage.dispose(); this purges the original image from memory, it may be different in the latest version, but the last version didn't clear up after images are not shown, and my games would crash after running out of memory filled with images that I was changing. ( in the example shown the code would be _myimage.dispose(); )