em ci

Hello, I have recently purchased a larger SD for my phone, and I wanted to move all my files from the old SD card to my computer first, and then back to my new SD card. However, after they got transferred to my PC, they went crazy. My folders 'compressed' and showed two blue arrows on top (I have tried to untick the 'compress file' from the secondary menu, but is not successful). Each of my photo now has 10GB!! No programme will open any of my photos. I can't move the whole file anywhere, as I need 27TB of space???? How on earth did that happen? They were coming from a small 32GB SD card. I have been Google'ing it, but don't even know how to address the problem, as it is way out of my understanding. If anybody could give me any advise, I would be very grateful, as I am losing a lot of important files. Many thanks.