We are looking to keep all of our images in CQ. One problem we are having is that we will have an image say flower.jpg in the dam but may also have a 10mb version of that file in a "hi-res" folder in the DAM. So I am wondering if there is a way to hide those "hi-res" images from showing up in in the content finder? I don't want to accidentally drag a 10mb+ cmyk image into a template.
Out of the box there is no option. In case authors are not using "hi-res" folder The simplest option would be deny permission for folder hi-res. There by it does not displayed in content finder. Another possibility (I am Guessing) would be create/overlay content finder tab  and see if you can set the filter to exclude the folder using the api.