Off the top of my head:
I would make a bunch of these frames in plain old black and white. Just paint with black in a single layer. Save the frames in a CC library for quick access. You can pull them out as needed. To have them be white, like your images above, simply invert them when you bring them in.
Once you have a simple set up like above - you can create some action to automatically apply them to your images.
Create a Shape
Draw the shape as a Path using the Pen tool. Make sure that your path is selected, and choose Edit > Define Custom Shape.
Name the shape and click OK. Now the new shape is stored and available.
To access it, click on the Custom Shape tool. Then click on the Shape: down arrow in the Options bar. The new shape is the last one of those displayed.
Click on it to select it.
Use a Shape
If the image layer is locked, drag the lock to the trash
Hold down the Cmd key and choose the New Layer symbol to place a layer below the image layer
Edit > Fill with white.
Return to the image layer
Choose the Shape with the Options bar set to Path
Draw the area to be the visible part of the image
Hold down the Cmd key and click on the mask symbol to create a vector mask, sharp in any size
EDIT: I neglected to mention that, in addition to Photoshop's Frame shapes, you may want to check out Google's "Vector Shapes Frames".