I am fetching data from RSS feed with Magpie.
$rss[description]  contains CDATA with html elements:  

&lt;![CDATA[  
&lt;div&gt;  
 &lt;a href='url'&gt;  
  &lt;img src='img_url' alt='aaa' title='bbb' border='0' width='116' height='116'&gt;  
 &lt;/a&gt;  
&lt;/div&gt;]]&gt;  
Some other text  


How can I fetch "img_url" from this?  Is preg_match() the only way? Maybe I can use simpleXML?


Question: Does the <h1> tag get more SEO value if there is no usable keyword in the URL?
Answer: If I understand your question right, no. It is a numbers game. Simple math really. Keyword in link + keyword in URL + keyword in path + keyword in resource name + keyword in &lt;h1&gt; + keyword in content = ?? There is no adjusting the weight of a keyword in &lt;h1&gt; because keywords are not found in the URL or path. However, having said that, search engines will use the keywords they find. If there are no keywords in some elements, then the keywords found become more important for search matches. Not more weight. Just what is available.

I hope I got your question right.