Quoting
cdwjava
Arguably, you cannot tell if the weapons are functional or real in a photo, you may not be able to determine with sufficient proof where or when the image was taken, etc.
Now, if they have testimony from others that you were, indeed, possessing illegal weapons or possessing them in a place you shouldn't have them (i.e. they verify what was in the photo) then you might be in trouble.
As I said, BY ITSELF, the photo is almost certainly going to be insufficient to establish that a crime was committed.