Missing docs/examples for decoder.next_image()

[Shnatsel]

The function decoder.next_image() is under-documented.

First off, it is not clear how this function relates to read_image() and what the difference between them is.

Second, the naive approach to using it does not compile:

fn decode(data: &[u8]) {
    let cursor = Cursor::new(data);
    if let Ok(mut decoder) = Decoder::new(cursor) {
        while decoder.more_images() {
            decoder.next_image();
        }
    }
}

This fails with the following error:

error[E0382]: borrow of moved value: `decoder`
  --> src/bin/tiff-afl-multi.rs:11:19
   |
11 |             while decoder.more_images() {
   |                   ^^^^^^^ value borrowed here after move
12 |                 decoder.next_image();
   |                 ------- value moved here, in previous iteration of loop
   |
   = note: move occurs because `decoder` has type `tiff::decoder::Decoder<std::io::Cursor<&[u8]>>`, which does not implement the `Copy` trait

A code example that uses it correctly would be appreciated.