Combining fields and avoiding duplicate display
I don't think this will necessarily fix your problem, but you're calling the theme_image_style incorrectly, it should be:

theme('image_style', array(
  'style_name' =&gt; 'thumbnail',
  'path' =&gt; $result['node']-&gt;field_image['und'][0]['uri'],
  'alt' =&gt; $title,
  'title' =&gt; $title,
  'attributes' =&gt; array('class' =&gt; 'search-result-img'),
));


Your second example is wrong, you can't call path twice.