Tailoring CB Gallery

And what about gallery auto action?

Not sure what you're asking. The gallery action doesn't let you supply custom PHP. You'd have to do any custom PHP processing after the action in the Output parameters or chain together 2 auto actions. Will review improving the gallery action this week to be able to create an album and media at the same time and if album exists already then to just add the media to the existing album.

Ok, latest CB Auto Actions release will let you create a folder at the same time as creating an item. There's a new Folder parameter in the action that lets you supply a folder id for a specific folder or a folder title. If title is supplied it will try to find a matching folder and add the item to it or create the folder with that title if one doesn't already exist then add the item to it.

Hello Krileon it just works perfectly, thank you so much!
Now what would you suggest for my users to share their albums to other users easily?

They should be able to just copy the URL when viewing an album and share that. If using CB Activity then you can publish the relevant system actions in CB Auto Actions to have profile gallery uploads/links show up on their activity feed.

As I understand an album can be viewed by anyone having the URL which consists of the following parameters:
domain.com/cb-gallery
?action=folder
&func=show
&id=1
&gallery=a934fb22b04dce2904e5adce9b14868b

To generate an album URL for a user I apparently just need to find the corresponding album ID and the rest of the URL can stay the same.
Am I wrong or am I forgetting something? What is the gallery parameter for (that contains a934fb22b04dce2904e5adce9b14868b)?