Problem Definition

Confluence treats each attachment upload as a new file at storage level.

This means that multiple uploads of the exact same file will add up to more storage space needed.

Suggested Solution

Implement data deduplication to optimize data storage utilization and costs.

Reference: Data deduplication - Wikipedia.

PS: Data deduplication is more commonly found at Storage-level technologies (such as Isilon NAS).

Workaround

It is possible to centralize attachments and add them to new Pages via Insert files and images > Search on other pages:

PS: If the original attachment gets deleted, all references will be lost as well.