[Windows Central Question]

I was manually backing up my photos onto an external HDD each photo on my phone copied into two photos on my HDD with th suffix 'Pro' and 'Highres' can someone explain to me about this?

[Zerveone]

Pro is the oversampled version of the image. If You have a Lumia 930/1520/1020 and your camera is either 20mp or 41 mp, Your phone automatically saves 2 pictures. One in full resolution and one is oversampled (fitting it into 5mp resolution with special algorithms, so the picture is weights less but it does not lose quality).
So in short:
Pro = oversampled 5mp (not full resolution picture)
highres = full resolution picture.

You can disable saving highres photos in settings of Lumia Camera app so it will only save 5mp version of the image.

[pratyk95]

ok i had the same question so i keep the 'highres' only if have some editing work to do on the image otherwise i'm better off just deleting it??

[dKp1977]

ok i had the same question so i keep the 'highres' only if have some editing work to do on the image otherwise i'm better off just deleting it??

Yes. I recommend the following though:
I regularly copy all my photos over to my Surface Pro/computer, including the high resolution ones. I then remove the highres images from my phone and keep the oversampled ones to save storage.