Binding the ContentPath of a Loader Component

I want to bind the ContentPath of a Loader component to a selected item in a datagrid. (This item is something like 'Image25'). When the formatter is set to 'none', I can refer to an item in the same folder.., but the images are in another folder (Images). Can I refer to this folder with the formatter 'Rearrange Fields' or ''Compose String' and which syntax do I have to use? Flash Help files are pretty short about this.