Please move if there is a proper 'software' sub-forum.

Am after re-purposing a retired/orphan 'smart' phone with no service, for surveillance/wildlife/trail snapshot photo camera triggered by motion; help!

If you know of any application that can work, please advise.
No video, no service provider, no wifi. Just hang a retired 'smart' phone on a tree; later grab the phone hanging from the tree and look at pictures taken since last hung. Ignore supplying power to it.

This is not about a smart phone to communicate with a wifi wildlife camera at a trail to download images nor remote viewing. It is a walk-to-the-tree, look at the images taken, erase the unwanted. Hang it up again. Simple basics. Cannot find such ☹️

Is it too much to ask ? Decommissioned old phones filling drawers doing nothing when they have on-board the camera, the memory for saving, the brains to do it, the connectors/links to do it... Is there a web site dedicated for re-purposing these very featured useable 'junk' ?

Found many complex applications all aimed to the lazy press a wifi button to get video remotely. Plenty of surveillance camera applications too, all for video. No motion triggered photos ☹️

Do phones have motion-activation capabilities?

You might look for an app that takes pictures at regular intervals. Time-lapse with a large gap. Most phones nowadays have a feature that records several seconds of pictures with each shot, which improves odds of capturing something.

The software determines changes in the image to trigger capture; no need to have a motion sensor on the phone. As far as I know.

Settings can be changes in the image 'every xx seconds' , or recognize human, or vehicle...