To completely remove the “Add Photos” link on the listing page, you can use this CSS code:
.content-single-job_listing-actions-start {
display: none;
}
This needs to be inserted, via copy/paste, into a brand new line at the bottom of your ‘Additional CSS section found by navigating to:
1. WP Admin
2. Appearance
3. Customizer
4. Additional CSS
Other than that, if you are using the child theme you can insert it within the style.css file of the child theme. This is a preferred way as it will not be affected by the next update.