how to get w3 total cache to cache my 'gallery' files (& apply ETags & Expires)

My Gallery files are in: (url)/wp-content/gallery/photos/

but W3 Total cache doesn’t seem to be applying Expires headers to them NOR Entity tags. How do I direct it to this folder?

Also, has anyone had any luck minifying nextgen gallery / smooth gallery files (css & Java) without breaking it?

When I combo the Js files it breaks. What am i doing wrong?

Thanks