iCloud & iCloud Photos · iCloud Photos and the Photos library
How do I recover a photo I deleted with iCloud Photos turned on?
Short answer: Open Photos' Recently Deleted album, select the photo and click Recover; it returns on every device. Items stay there for a limited time — after that you need a backup. Storage Studio never deletes from the Photos library.
Open Photos and look in the Recently Deleted album in the sidebar. Select the photo and click Recover — it returns to your library on every device. Photos keeps deleted items there for a limited time before removing them for good.
If it's no longer there, you'll need a backup — a Time Machine backup of your Photos library, or exported originals on an external drive.
Storage Studio never deletes photos from your Photos library. If you removed a duplicate file with Storage Studio's Duplicates window — for example an exported photo in Downloads — that went to Storage Studio's Recycle Vault (or the Mac's Trash if no external drive is set up), so you can restore it from there.