This quick tutorial will show you how to replace the default Drupal 7 file icons (the icons shown in the default rendered "file" field output).
Firstly, we need to copy the default folder of icons in to our theme which we can then replace with our new icons. This can be found in "modules/file/icons". Copy and paste this folder in to your theme folder e.g. "sites/all/themes/MYTHEME/images".Read More