How to recover photos back after resetting my iPhone?

• If you have been using iCloud Photos, enable it again in the Settings for Photos. If your photos are still in iCloud Photos, they will slowly come back. Get help with missing photos - Apple Support
• If you have been not been using iCloud Photos, your backups will include the photos and you can recover your photos by restoring the iPhone from the last backup you made before the photos vanished: Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

You can try if you can find them in your recently deleted folder, if they're not there you can see and find them in a backup