A Microsoft file hosting and synchronization service.
If you deleted the image files in OneDrive, log into OneDrive online (https://onedrive.live.com/) in a web browser, on the left, open the OneDrive Recycle Bin, are the files available there for recovery?
If not and you have already emptied the OneDrive Recycle Bin, the only hope you may have is to use a 3rd party recovery utility on your PC or device to try to undelete or recover the deleted files.