WordPress.org

You can use the WordPress plugin installer, or do it manually:

1. Unzip "Custom Field Images" archive and put the folder into your plugins folder (/wp-content/plugins/).
2. Activate the plugin from the Plugins menu.

Usage

You can add <?php custom_field_image() ?> inside The Loop in the theme files where you want them to appear. Be sure to check the settings so as not to have duplicate images.

For example, if you want them to appear only when viewing posts by category, add the above function to category.php in your theme directory and uncheck "Display in: content and/or excerpt" from the settings page.

You can also add [cfi] where you want the image to appear in the post content (not excerpt). By default, it is inserted at the beginning.

There is also an additional template tag, called get_custom_field_image() which you can use to display the images however you want. See template-tags.php in the plugin directory for more details.