This tutorial shows how to disable/enable lightboxes (in JoomGallery component) in Joomla 3.x templates.
Login to Joomla admin panel, navigate to Components, click on Joomla gallery and open Configuration Manager.
Open the Category View Tab, search for Entering Detail View and change default ‘fancyBox’ to ‘Thickbox3’.
Search for ‘Popup box original image’ and set it to ‘No’.
When both changes are done, press the Save&Close button.
Then open your site gallery page to see the changes.
Feel free to check the detailed video tutorial below: