Open Google Photos
Sign in to the correct Google account
Go to Photos
Select the first photo
Hold Shift and select the last photo on desktop, or tap and hold then select multiple photos on mobile
Tap or click the Trash/Delete icon
Confirm deletion
Open Trash/Bin
Tap or click Empty trash/Delete forever to remove them permanently
Repeat for other albums, shared items, and device folders if needed
Check Archive and Locked Folder and delete items there separately if needed