The way you want your images to layout is exactly the way Wexley template works. That is the template that the site you posted the link to is built on, the same as this one I built.
https://christinegregoryphotography.com/kisses
and you have the ablility to switch templates.
However, as an Avenue user myself I think you have a very good site. The autocolums setting in the index tweaking site styles menu adds a nice looking effect using original aspect ratios for the thumbnails.
my random views another Avenue Site.