How to unsync photo that was done with Itunes causing being unable to delete old photos that have a greyed trash button?

Hello josephfromduxbury,

Thanks for posting in the Apple Support Communities.

You're looking to remove photos that were synced from iTunes to your iPhone, right?

If we have that correct, you'll need to use a computer with iTunes signed in with your Apple ID. Instead of adding new photos to sync with your iPhone from iTunes, you'll sync to remove the photos. Be sure no albums are selected for Photos, but keep in mind that this may not copy the photos to your computer. The steps below will get you started, and you can continue to follow along with the next steps here: Sync photos in iTunes on PC with devices - Apple Support

1. Connect your device to your computer.

You can connect your device using a USB or USB-C cable or a Wi-Fi connection. To turn on Wi-Fi syncing, see Sync iTunes content on PC with devices on Wi-Fi.

2. In the iTunes app  on your PC, click the Device button near the top left of the iTunes window.

3. Click Photos.

We hope that's able to help.

Have a great day!