How can I delete photos from my iPhone 4 that has been uploaded from my iMac my memory is full on my phone now

I have an iPhone 4 8gb iOS version 7.1.2

Photos on my iMac have been uploaded to my phone and has filled up my available memory.

I want to delete the photos from my iPhone, there are 130 images which are hi-res.

How can I delete 130 photos from my iPhone they are in collections/moments.

I have tried many options in iTunes.

I can delete the pictures that have been taken on the iPhone 4 but not the ones that were uploaded from my iMac.