Quick question about file sizes

[Slappi]

I was moving my apple photo photos and movie to a usb flash drive today and the files are noticeably smaller. For an example.... A 500mb video transfers to the flash drive as 150mb. All the photos and videos did the same thing.

Why is this happening? Is the quality being downgraded?

Thanks!

 

[hallux]

Are you exporting the files or are you copying them using Finder?

If you're exporting them, the export process is likely compressing them as well.