Hello. It was already explained by the community to you in the comment section here.

Curated photography/photo contest tags are for submitting own and original photography, not someone else's (either bought or free use). Any photography that was not taken by the author of the post has to be clearly sourced.
Buying photography/photo art does not make you the author/photo artist who created the photos. Neither does it give you a copyright. They only give you a right to use for commercial purposes.
These photos are the main highlight of your post and are published in curated tags - by doing so you claim to be the author of these photos and claim copyright to them.

If you think that you can bulk drop photography into curated tags and photo contests that you purchased from stock websites to farm rewards, then you understood it the wrong way round.