Programmatically Apply image style in Drupal 7

We can set the image style programmatically in Drupal 7.

1. Configuration -> Media -> Image Styles -> Add Style
2. image_style_url('style_name', 'path');

Ref: https://api.drupal.org/api/drupal/modules!image!image.module/function/image_style_url/7
Example:
print image_style_url('thumbnail', $node->field_image['und'][0]['uri']);