photos

The photos with the exclamation marks are just previews and smaller versions of your originals saved in your icloud. It seems you have set your storage settings to optimize iphone storage, this will only store small version of photos and will require a internet connection to view them in hd.

if your phone has enough storage you can go to your icloud and optimize your storage to download and keep orignals.

check this out:

https://support.apple.com/en-us/HT205703

Most welcome :)

if you download and keep originals, that will not delete any of your photos. On the other hand, you will have a fully downloaded library to your phone memory and also have the same photos on all your i cloud linked devices.