Crop uploaded images instead of scaling them – http://www.catswhocode.com/blog/best-wordpress-snippets-hacks-and-tips-from-2013

wp_images_crop_dont_scale.php

<?php
// Standard Size Thumbnail
if(false === get_option("thumbnail_crop")) {
     add_option("thumbnail_crop", "1"); }
     else {
          update_option("thumbnail_crop", "1");
     }

// Medium Size Thumbnail
if(false === get_option("medium_crop")) {
     add_option("medium_crop", "1"); }
     else {
          update_option("medium_crop", "1");
     }

// Large Size Thumbnail
if(false === get_option("large_crop")) {
     add_option("large_crop", "1"); }
     else {
          update_option("large_crop", "1");
      }
?>