Working with Images in Drupal

gistfile1.php

// Using the Entity API
  $image = $MY_ENITIY->field_image->value();
  $variables = array(
        'style_name' => 'my_style__img',
        'path' => $centre['image']['uri'],
        'width' => $centre['image']['width'],
        'height' => $centre['image']['height'],
  );
  $img = theme('image_style', $variables );
  
// This however will not work wor with defaul images, you can use field_get_default_value() if comes back empty
  if (empty($image)) {
    $image = field_get_default_value(..)
  }

// You can also use add a view mode or the display settings to field_view_field()

// Load and render the filed (will work with default image) using a taxonomy term in the example
  $entity = $MY_ENITIY->value();
  $image = field_view_field('taxonomy_term', $entity, 'field_image');
  $image = render($image);