How to show multiple images in a slideshow for a portfolio page

A simple solution would be to use the featured image (post thumbnail) as image for the portfolio listing and for the item itself you can use the native gallery with its shortcode: .

Also if you’d like to use some kind of lightbox with it you can look/use the plugin
jQuery Lightbox For Native Galleries

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)