title: Rust - image crate: issue saving image buffer
body: <p>I have a question related to the fractal example (section '6.2 Generating Fractals', <a href="https://github.com/PistonDevelopers/image" rel="nofollow noreferrer">https://github.com/PistonDevelopers/image</a>) in examples supplied for image crate</p>
  
  <p>1) At line </p>
  
  <pre><code>image::ImageLuma8(imgbuf).save(fout, image::PNG).unwrap();
  </code></pre>
  
  <p>I get the following compile error message (rustc 1.25.0): </p>
  
  <pre><code>error[E0061]: this function takes 1 parameter but 2 parameters were supplied
    --&gt; src/main.rs:52:31
     |
  52 |     image::ImageLuma8(imgbuf).save(fout, image::PNG).unwrap();
     |                               ^^^^ expected 1 parameter
  </code></pre>
  
  <p>Thank you for helping!</p>
  
  <p>2) Note in addition that I had to change </p>
  
  <pre><code>use num_complex::Complex;
  </code></pre>
  
  <p>to </p>
  
  <pre><code>use num::complex::{Complex};
  </code></pre>
  
  <p>at the beginning of the example. Maybe crate num_complex does not exist any longer ?</p>