iPhone storage full

That will not help - iCloud stores the images in sync with your phone so that they can be displayed on any other iDevice you sign into - you actually have to import the images to your computer or an external hard drive and delete them off the phone

Import photos and videos from your iPhone, iPad, or iPod touch to your computer - Apple Support

Sync photos from your computer to your iOS device using iTunes - Apple Support

You may need to restart your phone for your re-adjusted space to show itself

Try that and see if anything changes

Do a forced restart -  After shutting down all open apps using the app switcher - invoked by quick double press of the home button and swiping up on each app till it flies off the screen.

Hold the sleep/wake and home buttons down together till you see  logo - then release and allow normal boot up

To perform a hard reboot on the iPhone X, press and quickly release the Volume Up button, then do the same for the Volume Down button. Follow up by pressing the Side button, and hold until the display suddenly shuts off — about 10 seconds. Keep holding the Side button and release when the device turns back onto its Apple boot screen. This is the same process the iPhone 8 and 8 Plus use to force-restart, too.