title: How to crop and then resize with Paperclip
body: <p>I have a photo attachment which I'm saving using Paperclip. However, I'd like to process the photo first before saving by cropping it down and then resizing to the final size:
  e.g. I have a 900x900 photo, I want to first do a central crop to 500x500, and then resize the cropped photo down to a thumbnail size of 100x100.</p>
  
  <p>The purpose of this is so that the thumbnail image wouldn't simply be a scaled down version of the 900x900 since it might be too small to even make out anything in the photo. By cropping it, we reduce a huge part of photo that can be left out and still have a meaningful scaled down thumbnail.</p>
  
  <p>I know paperclip can do either crop or resize, but is there a way to combine both?</p>
  
  <p>Edit: To clarify, I'm not trying to create a cropper tool where the user can interact and crop the image. For every photo that is uploaded, I want to uniformly perform a crop followed by a resize.</p>
  
  <p>Thanks</p>