This is the jig_ng_pure_request_uri_for_recent_galleries filter for developers.
A very tiny addition to your site, but it could have a nice impact. It lets you redirect the NextGEN Recent galleries feature's links (on the thumbnails) to a central page where you already show your albums or galleries, /albums/ - instead of adding the /nggallery/... parts to any page the original JIG happens to be on. This makes the Recent galleries feature usable in sidebar or footer without "straight to lightbox" mode.
The way you use it is really simple. Just return the path to the page you normally use for your albums and galleries. It needs to have a JIG in a primary, above the fold position on the page in question. Leading and trailing slashes are mandatory. Do not specify your host/domain.
The name - request URI - comes from PHP $_SERVER variables.
You receive the original $uri, which is very similar to what you'd return but it could be any page your Recent galleries JIG appears on. You'd get /contact/ or similar from a contact form. As you see, this information is not too important.