This LibreOffice plugin adds a new toolbar button and an edit menu command: “Paste with credit”. When that is used to paste an image, copied with metadata from a web page using the Firefox addon (version 0.3.0 or later), a credit line with attribution and license information will be added to Writer documents. It is then possible to copy this image with the metadata by rightclicking on it, much like the Firefox addon.
In Presenter documents the metadata will just be stored with the image on paste, and a text box can be inserted with “Insert->Credits” listing all the pasted images with metadata.
Currently only LibreOffice on Linux (or other X Windows desktops) is supported. On MacOSX, it is possible to copy and paste within the same LibreOffice instance but not between applications (and it seems to be the same on Windows).