Toob, welcome to FF.
you cannot open an image in the workflow. all the image component does is display an image that you've opened in the main user interface. you cannot use the image component to actually open an image.
if you have an image open in the main display and then go into the editor, you'll see in the little preview window of the image component a display of the image you opened in the main interface. that's it.
you can then plug the image component into other components and alter the inputted image via the various other effects of the components. but you cant input a new image directly into the image component from the editor interface.
and, you can only have one imported image open at a time in filter forge. hopefully, down the road, this will be expanded so that you can have more than one, but not now.
If wishes were horses... there'd be a whole lot of horse crap to clean up!
Craig