Snap the weekly store schedule. This page reads it on your phone, keeps only your row, and adds those shifts to your calendar. Days you're not on are left off.
Last name is usually enough. Saved on this phone for next time.
Names found on the schedule. Tap yours:
Shifts go into your default calendar. To use a different one, change it in Settings → Calendar → Default Calendar first.
Works with Outlook and most calendar apps. You can also import it into Google or Yahoo Calendar on a computer.
Apple Calendar: if a schedule changes, scan the new one and add again, and matching days update instead of doubling. Google and Yahoo add each shift as a new event, so delete the old one if a shift moves.
Photos never leave your phone. In Safari, tap Share → Add to Home Screen to keep this like an app.