Q: i made a mistake copied all photos from my comp to my iphone how do i remove some of them

You remove them by syncing to your computer again using iTunes but change the selection of the photos that you want to sync. Each time you sync with iTunes it adds or deletes photos to the phone as needed to make the synced photos on the phone match the selection in iTunes on the computer. The following link has instructions, including a section on how to delete all of the synced photos on the phone (although that isn't necessary if you want to retain some.) Sync photos from your computer to your iOS device using iTunes - Apple Support