[Jetpack] Use photon to serve Post thumbnails, with custom cropping, and a different cropping on single pages:

plugin.php

<?php
if( function_exists( 'jetpack_photon_url' ) ) {
    add_filter( 'jetpack_photon_url', 'jetpack_photon_url', 10, 3 );
}
function jeherve_display_custom( $content, $post ) {
 
    global $post;
 
    // If you didn't define a post thumnail, let's forget about all this
    if ( !has_post_thumbnail( $post->ID ) )
        return $content;
 
    // What's the cropping and the size of image we should use on Single pages?
    // See <a href="http://developer.wordpress.com/docs/photon/api/#crop" rel="nofollow noreferrer">http://developer.wordpress.com/docs/photon/api/#crop</a> for parameters
    if ( is_single() ) {
        $args = array(
            'crop'   => '50,50,200px,200px',
        );
    }
    // resizing on other pages
    else {
        $args = array(
            'resize'   => '200,400',
        );
    }
 
    // Let's create a Photon Image URL from the Post Thumbnail
    $feat_image_url = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'full');
    $photon_image_url = jetpack_photon_url( $feat_image_url[0], $args );
 
    // Let's build the image tag, as it was built before in your example
    $our_image = sprintf( '<div class="post-media"><a class="featured-image" href="%1$s" title="%2$s"><img src="%3$s" class="wp-post-image" alt="Featured Image"></a></div>',
        esc_url( get_permalink() ),
        esc_attr( sprintf( __( 'Open %s', 'dot' ), get_the_title() ) ),
        esc_attr( $photon_image_url )
    );
 
    // Let's return the image, right before the post content
    return $our_image . $content;
 
}
add_filter( 'the_content', 'jeherve_display_custom' );