Thank you so much for your reply.
I've modified the Query:
SELECT pg1_gallery_images.id, file_prefix, pg1_gallery_images.title, description, full_Description, pg1_gallery.folder_name
LEFT JOIN pg1_gallery_images
ON pg1_gallery_images.gallery_id = pg1_gallery.id
However, with no luck.
Here is the code for the image on the page:
<img src="../gallery_engine/images/<?php echo $row_WADApg1_gallery_images['folder_name']; ?>/<?php echo $row_WADApg1_gallery_images['file_prefix']; ?>" name="image">
Thank you so much in advance.