Missing thumbnails in image previews on product page

If you upload an image but the preview thumbnail is missing this is probably because the image size is too large.

You can update the maximum permitted thumbnail size by using the following filter:

	<?php
	/**
	* Increase maximum uploaded thumbnail size
	*/
	function prefix_dropzone_max_thumbnail_size( $size ) {
	return 1000;
	}
	add_filter( 'pewc_dropzone_max_thumbnail_size', 'prefix_dropzone_max_thumbnail_size' );