How to delete synced photos on iTunes to create more space for my iPhone 5?

How do I delete synced photos on iTunes to create more space for my iPhone 5?

Added (1). when i untick folders on 'photo library' and apply that, i still get no space on my phone which i deleted over a 1,000 photos.

Ok, it won't sync photos anymore but you'll still need to delete them from your device. As for memory, pictures alone don't take to much space.

Check your device for what else is taking up storage by going to your settings app
General>usage