Well if you want a Drupaly solution you could try installing the CiviCRM Entity module along with the Views in Contact Pages module
With CiviCRM Entity you can add Drupal fields to CiviCRM entities, so you could add you a normal Drupal image field and get all the wonderful goodies Drupal provides such as image styles.
Now this field data would live in Drupal field table not in CiviCRM custom field tables.
You add your field on the CiviCRM Entity Contact entity Manage Fields page at admin/structure/civicrm-entity/civicrm_contact
If you can live with the data being in the Drupal DB, not the CiviCRM db, then this can work for you.
Then if you want to display the image on the CiviCRM backend admin contact summary page, you use the Views in Contact Pages module to create a view that displays the image, along with any other data you want, and put that view either as a tab on the contact page, or a pane on the Summary tab.