How can I delete photos from the photo library in iOS 8? I'm using an iPhone with iOS 8.4, and a Mac with Yosemite using the Photos app and syncing with iTunes. iCloud Photo Library is turned off on both the Mac and the iPhone.

After syncing with iTunes there are photos on the iPhone that should not be there; they are not included in the "selected albums" list in iTunes. Some of them are no longer in my Photos library (on the Mac) at all. But after many syncs they still appear on the iPhone.

When I look at the offending photos there is no trash can icon (like there would be if they were in the Camera Roll), and tapping the Edit button brings up the message "This photo is not editable".

How can I delete these rogue photos? An ideal solution would be one that actually "syncs" my phone to the selected albums list in iTunes (ie. removing any photos that aren't in that list). But a way to manually delete photos would also be appreciated.

Edit: None of the photos in question were ever shared with iCloud sharing. They do not appear in any Shared Albums, and turning off iCloud sharing has no effect.
The only way that I have been able to delete photos that didn't have the trash can icon is with an app called Cleen.  Available from the Apple app store. I don't remember if it was free or not.  Once downloaded, pull the app up and you will see all your photo albums listed.  Click on the album that contains the photos you want to delete, which is probably the All Photos album.  When the next screen pops up, you will see the first photo in that album in the center of the screen.  Then you will see a little row of blank squares going across the top and bottom.  All you have to do is swipe the photo shown up, if you want to keep it, or swipe it down, if you want to trash it.  Keep going through the album until you get to the photos that you want to delete.  (Just in case you have some photos that you are not sure if you want to keep or delete, you can swipe them to the left and decide on them later)  Once you get those photos that you want deleted in the bottom row, hit the trash can.  The next screen will show you all the photos that are being deleted and if all is okay, hit Delete at top right.  Then a message will pop up saying "Allow Cleen to delete photo from album" and then you click Delete All.  It sounds like a lot, but it is really easy.  Doesn't take hardly no time.  I hope this helps you.  This is the only way that I have been able to delete photos when there was no trash can option available.