twice as many pics when I download to computer

[jfhj2]

Hello. I finally decided to download pics off my phone to computer and when I open the file they are in, there is 2 copies of each pic. One is large size, 2560 X 1920, and the other is 320 X 240. This hasn't always been like this looking through past pics. I have no idea why this is now doing this but would really like to know how to stop it so only the large ones download. Thanks