Thanks for your question. The ChatGPT questions are somewhat misleading. The mla_output= parameter is used primarily for pagination controls and has no role in the use of Photonic to display a gallery. There is no mla_gallery_custom_output parameter or feature in MLA.
You can use the [mla_gallery] shortcode to select the Media Library items for your gallery and then hand off control to Photonic to format the gallery. This is described in the “Support for the “Photonic Gallery for Flickr, Picasa, SmugMug, 500px and Instagram” Plugin” section of the Settings/Media Library Assistant Documentation tab. Of course, you must install and activate the Photonic plugin on your site to use it with MLA.
For example, here is a very simple shortcode that displays three items from the library:
[mla_gallery ids='9757,9512,9150' main_size='full' tile_size='full' style='masonry']
In this example, the ids= parameter selects the items. The style= parameter activates the Photonic support. The other two parameters are passed on to Photonic to format the gallery.
I am marking this topic resolved, but please update it if you have problems or further questions regarding MLA’s support of the Photonic plugin. Thanks for your interest in MLA.