NO! :mad: Don't spawn new links, especially not for a photo gallery. Just open the link in the same window, like every other link. If God* had intended links to be opened in new windows, he would have made that the default action.
Popup links should only ever be used in exceptional circumstances. A photo gallery is not an exceptional circumstance. Popup links are confusing and irritating, particularly with the advent of tabbed browsing, where they too often open a new window rather than a new tab. Any vaguely competent web surfer can choose to open a normal link in a new window/tab if they want to, but only a small proportion of the Enlightened One Percent† will be able to open a "target=_blank" link in the current window if they want to (after having found out the hard way that it's a popup link, of course).
* In the context of the Internet, that is of course Sir TBL.
† ie Opera users