[Plugin: wp-post-thumbnail] image alt tag problem

Dear fr8

i need little help, i found wp-post-thumbnail not show image alt name so can you tell me how can i add alt name on thumbnail image given at the time of save thumbnail at post published. i already set alt for all image but does not show in page.

script show only <img class=”thumbnail” src=”<?php echo get_post_meta($post->ID, “thumbnail”, true); ?>” alt=””/>

and sorry for my bad English.