inserting content into node using field
To do this in a template, 
1. create a file inside your /sites/all/themes/YOURTHEME folder, called node--CONTENT_TYPE.tpl.php.
2. copy the contents of node.tpl.php into that file.
3. add something like the following to the template file, where you want to print the image:

&lt;img src="http://example.com/&lt;?php 
    print $node-&gt;YOUR_FIELD_1[$node-&gt;language][0]['value'] . 
    '.' .
    $node-&gt;YOUR_FIELD_2[$node-&gt;language][0]['value']; 
    ?&gt; 
 alt="..." ... &gt;


Another possibility (probably better), would be to use the filefield sources module, and let the users upload the image to your drupal site by pasting the url.