Engagement is still decreasing...

At 11k followers I was getting 1.1k likes per picture, this has steadily decreased, and now at 19k I am getting 800 likes per photo.

This is very irritating, do you guys think it is worth follow/unfollowing still, or will my engagement just continue to drop?

I dont know dude ive seen some pages with over 1 million follower and they only have 1.5% engagement, try different things to actually engage your followers for example if you are in a fashion niche ask people to upload their favorite shoes and tag you at the end of the week whoever 1 random winner would be chosen to be featured on the page this gets people who are already interested in your niche to participate more and when they tag you their friends see you too so this way you get tons of engagement and new followers!

Very odd but not uncommon. Did you take a break from posting? Maybe change your content a bit different from what you had been doing before? Trying following more targeted followers in your niche, maybe people who liked photos on a certain page in your niche etc. This should increase engagement.

Depends on what platform but think about it this way. There's only a finite pool of people interested in every niche - okay - in a huge niche this could be millions but in a smaller niche it could literally be hundreds only.

What I'd suspect is happening is that the pool of people interested in your stuff has "discovered you" and are now bored - especially if you're spamming the same deal every day.

IMHO change thing, try new ideas and test what works. Once you find something keep allocating some time / budget so you can keep finding new ideas to keep engagement high.

Engagement is something that has to do with your content and a good interaction strategy. If you are posting scraped photos, it will sooner or later, irritate your followers resulting a low engagement rate. Try to post mix content (fresh and scraped photos with a mix of a few Vines in a week) with a good engagement strategy (e.g. content/freebies/rewards etc).

Secondly, control or slow down your content posting frequency. If you use FL, run a separate project for manual content posting at different times of the day (of course, keep a sync with the country clock of your followers).

Tx..