Don,
You will have to add support for thumbnails in your functions.php/plugin-file.php
//Add Support for Thumbs
if ( function_exists( 'add_theme_support' ) ) {
add_theme_support( 'post-thumbnails' );
set_post_thumbnail_size( 960, 276, true ); // default Post Thumbnail dimensions
}
//Add Thumbnail sizes
if ( function_exists( 'add_image_size' ) ) {
add_image_size( 'large-thumb', 960, 276, true ); //960 pixels wide x 276 height and cropping
add_image_size( 'medium-thumb', 605, 174 ); //No crop
add_image_size( 'small-thumb', 288, 83, true );
}
From here you can modify this output in your loop to work for your needs:
<?php if ( has_post_thumbnail() ) {
echo '<a href="' . get_permalink( $post->ID ) . '" title="' . esc_attr( $post->post_title ) . '">';
echo get_the_post_thumbnail($thumbnail->ID, 'small-thumb', array( 'alt' => esc_attr( $post->post_title ), 'title' => esc_attr( $post->post_title ) ));
echo '</a>'; //Change the 'small-thumb' to whichever size you would like.
}
Hope this helps you figure out what you’re doing – if you need any help building a Query for this I you should look into this page.