<?php

					//custom image:

					$meta_values_for_image = get_post_custom_values('preview_image');
					$preview_image_ID = $meta_values_for_image[0];
					$imageSrcArray =  wp_get_attachment_image_src($preview_image_ID,array(200,300));
					$imageSrc =  $imageSrcArray[0];

					echo $imageSrc;
				?>