How to delete synced photos from iPhone without connecting to mac?
Synced Photos deleting must be done through iTunes. To do so just:


In iTunes select the device icon in the Devices List on the left. Click the Photos tab in the resulting window.
Choose Sync photos from, being iPhoto or Aperture on a Mac and Photoshop Album or Photoshop Elements on a Windows PC.
Choose Select Albums and deselect the albums or collections you want to delete.
Click Apply.