Q: how do i removed photo's sync'd to my phone from my computer?

You remove them by syncing again but change the settings/selection on the Photos page of iTunes before doing the sync. Instructions below are from Sync photos from your computer to your iOS device using iTunes - Apple Support

Delete synced photos

1. In iTunes, locate and click on your device.
2. Click Photos.
3. Choose "Selected albums" and deselect the albums or collections you want to delete.
4. To delete all synced photos, deselect "Sync Photos from" and, when asked, click "Remove photos."
5. Click Apply.