Function for showing thumbnails for nodes with imce I am looking for a function, to show thumbnails for nodes.
There are some sized defined in imce and I want to show on of these.

This is my current function which puts out only the large Version of the Image:

if (isset($content['field_image'])) {
    echo render($content['field_image']);
}


What would be a correct Drupal 7 conform function the show the 'medium' thumbnail in the node template?
You can change style output in display fields settings of your content type. This will affect you render. 

Also you can use theme_image_style function to set your image style

Url of image you can find in $content['field_image']['und'][0]['uri']