Featured image is one of the good looking feature introduced in wordpress3.0. In TwentyTen by default featured image will not display in category loops, where as they will display properly in the front page. This is because the archives are using ‘the_excerpt()’ to show a short part of the post; while the front page is using ‘the_content()’. If we want to have featured image in category loops we need to modify some part of the code.
1. Go to Dashboard
2. Go to Appearances
3. Click Editor
4. Open loop.php file
5. Search the following lines
<?php if ( is_archive() || is_search() ) : // Display excerpts for archives and search. ?>
6. Replace the above code with below code
<?php if ( is_search() ) : // Display excerpts for search. ?>
This will occur in two places, replace both of them and save !!