JPG files that seem to take up 16 GB space (but 8 kB on disc) and cannot be opened

Hello. Thanks for explaining the issue, sorry this happened while copying your photos.

This behavior points to an interrupted or incomplete file transfer from the phone, which leaves zero-content JPG files with incorrect size metadata. Extreme file sizes and no app opens the files because the image data never wrote correctly. Windows does not alter image contents on copy. Recovery depends on whether the original photos still exist on the phone or in a synced service.

If the photos still appear on your Galaxy or in Samsung Cloud or OneDrive, reconnect the phone and copy again using the supported USB file transfer method, or download them directly from the cloud. If the originals no longer exist, corrupted files without image data cannot be rebuilt by the system. The reliable next step is to recover from the original source or backup.

I'm not sure what has happened specifically in your case.

With OneDrive, you don't need to make copies because your OneDrive folder is mirrored across all your devices.

On Windows, with the backup feature ON, the Desktop, Documents, Pictures, Music, and Videos folders are automatically included in OneDrive. Copying from OneDrive and pasting into these OneDrive folders will create duplicates.

If you do make copies, they should be saved in folders outside OneDrive.