Photo Gallery Forums

I've undestood that if I want to change background of a theme I've to duplicate the theme and modify it. I would like to have a fullscreen image as background and I'm asking if someone could give me some directions on how to do that. Maybe I've just to replace a file and maybe not but I don't want to mess up everything. Thanks...

Thats right. Basically, you need to create a copy of the theme before you edit it. This is so that the original is kept in tact, and also makes it easier to upgrade and keep your own theme unchanged.

Create your new theme (from an existing theme), and click to edit the new theme. On the far right, you will see a button "Upload Background":


The image will upload into the theme folder, and you can then select it from background URL setting:
style -> background image -> Url



Finally, set the scalemode to noborder:


For reference, more info on themes here:
https://www.photo.gallery/documentation/edit-themes/

Thank you very much!