• For Apple devices
Now new versions of iOS (which your iPhone regularly offers to download) have a tool to recover deleted photos simply from its phone. Just go to the "Photos" application which brings together all your images and videos. In the "Albums" tab, select the "recently deleted" file. All the photos and videos that you decide to erase end up in this file for 30 days.
To recover them, click on "Choose" at the top right, then choose the photos you want to keep. Finally click on "Recover" at the bottom right to find the image again in your photo gallery.
You can also find your photos by restoring your device from your computer. To do this, you must first back up your phone by plugging it into your computer and connecting it to the iTunes software.
To learn more about this method, see: Backing up data on iPhone