Add image to gallery via PHP

See the template tag usage on the front page
https://www.ads-software.com/plugins/easy-image-gallery/

Is that what you are after?

Solved by myself! ??
I had to upload some images to a post gallery, and I find out that I must simply add the images’ IDs in the “_easy_image_gallery” meta field using the WordPress funcion “add_post_meta”

Ahh I understand now, yep that’s correct! Glad you worked it out.