Depends on where they were and how long ago they were removed.
1. If they were on a different device only, then you can only get them off that device.
2. If they were in a google, gmail, cloud, etc., account, then you will have to download them from there.
3. If they were deleted off your phone a long time ago (even a week) they may not be able to be gotten back, by any means, due to the phone overwriting that space with new data.
4. While there is no guaranty that you can get them back. Deleted does mean deleted. There are a few apps/programs out there that 'may' be able to help you recover the data.
A few of the programs you could try would be... DiskDigger, MobiSaver, Android-Recovery and Tenorshare. They are all data recovery...