Custom content type show taxonomy image
The easiest answer to your problem might be the taxonomy image module:


  "The taxonomy_image module allows site administrators to associate
  images with taxonomy terms. With the association created, an admin can
  then make a call to 'taxonomy_image_display()' from their theme or
  other PHP code to display the appropriate image."


but since you already have a field associated with your taxonomy term, you just want to suppress the output of the tags in your node template and replace it with code that loads the term field and then renders it, ex. roughly:

/* load your term object */
$term= taxonomy_term_load($node-&gt;field_tags['und'][0]['tid']);

/* load the entity object (your field names will vary)
$result=field_view_field('taxonomy_term',$term,'field_image','image');

/* display the rendered result, this can be set in manage display for your field to use image styles, etc. */
print render($result);