It is possible to move an Attachment from one object (Project, Portfolio folder, Work Package) to another.
Log in to the HTML5 client.
Select the Attachments sub-tab available in:
The Project Card, Library Items tab, if attachments are managed at the Project level.
The Portfolio Work management workspace, if attachments are managed at the Portfolio level.
The Work Package Work management workspace, if attachments are managed at the Work Package level.
Select a project, a portfolio folder, or a work package in the selector.
In the spreadsheet, select the Attachment you want to move to another object.
Click on the Move () button, and select one of the following commands:
Move to Portfolio Folder
Move to Project
Move to Work Package
Select the object in the list.