You can only recover photos on Android HTC phone in 3 cases, they are: If the phone has an option of Recycle Bin in the gallery app through which you can get those pics back. If you have stored those pics in multiple sources or backed up those pics onto your PC for safety. Or if you have stored or backed up the photos on some cloud storage such as Google Drive, Onedrive, or some proprietary cloud service provided by HTC.
