I have a table in Postgres 9.5 with this structure:
my_table (id Integer, images_ranks image_rank[]);
where image_rank is:
The best would be for you to use this excellent library: https://github.com/tminglei/slick-pg
If you would rather implement it yourself, have a look at the source code (https://github.com/tminglei/slick-pg/tree/master/core/src/main/scala/com/github/tminglei/slickpg/array) and get what you want from there.