I had this problem as well. Turns out the problem lies in the function that fetches the featured image.
To fix this, open the file shop-loop.php located in [root]/wp-content/themes/salejunction/lib in a text editor and find line 70 (I recommend something like Notepad++ or SublimeText2 for this, as they give you line numbers).
The line originally says “<?php get_the_post_thumbnail_id(); ?>”, which is wrong.
Replace it with “<?php the_post_thumbnail(); ?>” and it should work fine!
