Best interface to select image files from the system file tree

I am creating an application that does various things to one or many image files specified by the user.

I have the form in the image attached which shows the user their system directory tree (as the app is in development it only shows H:/ drive)

I only want the tree to show the images that are in the folders, which it does currently (see in the root directory that there are three image files, there are other files in H:\ of different types that are excluded from the view)

I don't know if it is confusing for the user to see empty folders (IE no image files inside) although I would think that it is less confusing than ommitting those folders completely?

Another thing is, if the user clicks the box representing the root directory (H:) that selects all the displayed files and folders below but they could empty, so selecting that folder is not going to do anything.

Can anyone offer advice on what the "best" method is here for allowing a user to select multiple picture files from various folders in the directory tree?