There are possibly two ways to get back deleted photos from SanDisk pen drive:
Way 1: From Backup
If you have kept the backup of your deleted photos somewhere else such as in computer hard drive, external HDDs, memory cards or cloud backup such as in Google Drive, Dropbox, etc, then you can easily restore your photos from the backup.
Way 2: Use SanDisk Pen Drive Data Recovery Software
In case, if you do not have, the in such situation you must try Photo Recovery which is a suitable SanDisk Pen Drive Data Recovery software. It is designed to recover deleted photos from SanDisk pen drive. Beside photos, the software also retrieve videos and audio files from various storage media devices such as computer hard drive, external hard drive, memory cards, digital camera, mobile phones and other data storage devices.