photos

Welcome to the Apple community.

Do you have a back up, if not you are out of luck I'm sorry.

The following may help (assuming you are using iCloud Photo Library):

On your phone, open the Photos app, tap Albums at the bottom, tap Recently Deleted, tap Select then tap Recover All or select individual photos and then Recover.

or

Use a computer browser to log in to https://www.icloud.com/ then click on the Photos app there. Click on Albums at the top of the window and then click Recently Deleted just to the right of Albums.

I'm assuming you have deleted them from the deleted folder, but worth looking as suggested by Foxfifth.

Also, if you did not have iCloud Photo Library on (in Settings > iCloud > Photos) but you did have iCloud Backup turned on (in Settings > iCloud > Backup), note the following in case you aren't already aware of it: photos are included in backup but you cannot see the contents of a backup at iCloud.com. You would need to use the backup to do a full restore of your phone -- and also note that doing that will erase any photos (and anything else) on your phone that are after the time of the last backup.