David:

You have an old box. Note the bare copper wires under the strain reliefs. You need to dig them out.

These http://www.zoro.com/i/G3705676/?utm_...Zo7 AodHwgAKQ ground clips are eused in that situation.

They are a bit difficult to attach, but The secure a solid pigtail to the side of the box. e.g. the edge that's exposed.

What I use in this case is an ground Ideal Term-a-nut. See http://www.grainger.com/product/IDEA...ctor-Nut-4YD75

So, you can dig out the bare ground. Install the term-a-nut and a solid pigtail. The solid pigtail goes to the ground clip and the free end of the term-a-nut (fork terminal goes to the green screw on the outlet),

With multiple GFCI's you would want to not series the GFCI. e.g. One GFCI protects the outlets down stream.

What can cause nuisance tripping is shared neutrals. The term is shared, but think of it as neutrals attached as "T-splices"

GFCI's do not need a ground, but if they don;t have one, they must be labeled that there is no ground.

You are not supposed to rely on the screw connection from the box to to the outlet, although some outlets are designed so it's OK.

Your house looks like it had original had two prong outlets and the upgrade wasn't done correctly. The conversion can be a pain, but the term-a-nuts make the job much easier.

When there is a threaded hole in the box that can accept a ground screw, then other ways are possible.

So far, I've never tapped a ground hole.