My MacBook Pro is running out of space so I recently bought an external hard drive with the intention of backing up my files and then deleting a ton of old photos/videos to free up space on my MacBook Pro. I plugged in the external hard drive the other day and completed a complete back up using Time Machine. My question is now that I am planning to delete many of my old photos/videos, won't Time Machine "overwrite" my library of photos/videos to mirror the new, cleaned up library on my MacBook Pro? For example, if I now have 100,000 photos/videos and I want to delete 70,000 of them on my MacBook, won't the Time Machine backup only reflect the 30,000 files left? Although I want those 70,000 files off of my MacBook's hard drive, I do want to be able to easily access them from my external hard drive if I need to pull them up in the future. I know this is simple, but I want to be 100% comfortable before i delete anything off my MacBook. Thank you for your help!