Images from media library not showing in category list

Your theme may be using <?php the_excerpt();?> instead of <?php the_content();?> in its template files. Try editing the relevant template file(s) and replacing <?php the_excerpt();?> with <?php the_content();?>

Hmm, I found one instance of <?php the_excerpt();?> and replaced as suggested, that was in archive.php. The result was that the category displayed the entire posting but still no thumbnail…

Any ideas on where other instances may be?

It definitely sounds like a theme issue but you’d need to go through all of the theme’s files to find the source of the problem.

Could this be the source? I found it in ‘functions.php’

# Displays post image attachment (sizes: thumbnail, medium, full)
function dp_attachment_image($postid=0, $size='thumbnail', $attributes='') {
	if ($postid<1) $postid = get_the_ID();
	if ($images = get_children(array(
		'post_parent' => $postid,
		'post_type' => 'attachment',
		'numberposts' => 1,
		'post_mime_type' => 'image',)))
		foreach($images as $image) {
			$attachment=wp_get_attachment_image_src($image->ID, $size);
			?><img src="<?php echo $attachment[0]; ?>" <?php echo $attributes; ?> /><?php