First upload the pictures to your PC and then add the pictures to iTunes.
1. Click here for instructions on how to add the pictures to iTunes.
2. Click on the Syncing photos to iOS devices.
3. Scroll down to Sync photos from a folder on your hard disk to your device and follow the steps provided.
Once the pictures have been added to iTune you can sync your iPhone 4S to iTunes and transfer the pictures to the another phone or computer.
Besides what i mentioned above, you can refer this article about How to transfer photos from iPhone 4s to iTunes on PC.
Hope it can do you a favor.