Open the Photos app on your iPhone, iPad, or Mac, or go to iCloud.com
Sign in with your Apple ID if needed
Select the pictures you want to delete
Tap or click the Delete icon
Confirm the deletion
Empty the Recently Deleted album to remove them permanently
On iPhone or iPad, open Photos, go to Albums, then Recently Deleted
Select the photos, then tap Delete All or Delete
On Mac, open Photos, select the photos, press Delete, then empty Recently Deleted
On iCloud.com, open Photos, select the photos, click Delete, then open Recently Deleted and delete them again
Turn off iCloud Photos only if you do not want future photos to sync to iCloud
Delete photos from all synced devices if you want them removed everywhere