Q: Deleting photos from iphone 5

You use iTunes to delete synced photos. It will only affect synced photos and does not delete any photos other than ones that were placed onto the phone via iTunes sync. The following procedure can be used when you no longer have access to the originals: Delete photos and video synced from iTunes when you can’t access the originals - Apple Support

Note however that it will delete all synced photos. If you have some synced photos that you want to keep, you would have to have access to the originals and you would then sync again to put them back on the phone.

This method is not longer possible in iOS 8.3 bu there are many methods to delete photos from yoour iPhone by using windows PCs, Mac, and iPhone without a strange thord parity app in the post linked bellow cantanis these methods and more.
Thanks

https://plus.google.com/110048656132173113003/posts/WEifaP7WnYg

http://iphonphone.blogspot.nl/2014/01/how-to-delete-photo-from-iphone.html