Using GarageSale Version 7.0.16b2 (839), macOS Version 10.13.6 (17G65)
In Editor Mode, image pane, select photo, select Edit Menu Copy command.
Finder, Edit Menu, Show Clipboard command shows contents: unknown.
Preview app, File Menu, New from Clipboard command dimmed.
Pages app, and try to Paste beeps.
In prior v7 versions, a valid photo image was placed on the Clipboard when doing a GarageSale Edit Menu Copy command with a photo image selected in the Editor Mode photo image pane.