If the phone was connected and set to automatically send the files to say a google account, then you can try logging into said account. Or if you had another form of back up set up on the phone. Also if you had the files saved to another device, say a computer, then you can get them back from there. Alas, if none of these has been done, then the images and other information is gone. No way to get it back.
This is why I tell people always back up your stuff regularly and to something off the device. So many back up to say a SD card, which is then in the device. Well that is of no help if it is lost or stolen. So in the future, back up anything you want to save to say a computer or google account, etc.