title: Using Picasso with custom disk cache
body: <p>In <code>Volley</code> library, the <code>NetworkImageView</code> class requires an <code>ImageLoader</code> that handles all the image requests by searching for them inside an <code>ImageCache</code> implementation, the user is free to choose how the cache should work, the location and the name of the images. </p>
  
  <p>I'm switching from <code>Volley</code> to <code>Retrofit</code>, and for the images I decided to try <code>Picasso</code>.</p>
  
  <p>With the former library, I had a String parameter in each of my items containing the image URL, then I used <code>myNetworkImageView.setImageUrl(item.getURL())</code> and it was able to determine if image was cached on disk. If the image existed in cache folder, the image was loaded, otherwise it was downloaded and loaded.</p>
  
  <p>I would like to be able to do the same with Picasso, is it possible with <code>Picasso</code> APIs or should I code such feature by myself?</p>
  
  <p>I was thinking to download the image to a folder (the cache folder), and use <code>Picasso.with(mContext).load(File downloadedimage)</code> on completion. Is this the proper way or are there any best practices? </p>