I have an Iphone 4s and a Windows 7 PC. When I plug in my phone it is recognized, but when I open the pictures folder (DCIM) there are only 2 folders showing. One shows about 30 pictures, 1 video, the other shows about 70 pictures, 3videos. I have just over 1500 pictures on my actual phone, I'm looking to back them up onto the PC but why are they not all showing? I've tried unlocking the phone first. Please help! Thank you.
Have you enabled iCloud Photo Library? If you have, go to Settings > Apple ID > iCloud > Photos to see whether you tick on "Optimise iPhone Storage". If you've ticked on this item, then that will explain your situation. If you enable this feature, it's normal for you to see just a few photos showing on the picture folder, because the rest of your photos is optimised to thumbnail and won't be shown on computer.
In this case, you should check your iCloud. All photos in your iPhone 4s will be stored there.
If you want to sync data from your iPhone with Windows always use iTunes.
You can download it here: https://www.apple.com/itunes/download/
iTunes is the official software from Apple to sync data from your iPhone with an other device and crucial for your iPhone when communicating with Windows.