Posting about Thickbox reminded me of this lightbox jQuery plugin, which has become my current fav for putting together quick galleries (like for flickr feeds and such). I'm also a sucker for the nice design at the site. And, as an extra bonus, picking through the source of this page is how I originally found the idTabs plugin (way back when this plugin was originally released), which has become one of my most frequently used plugins.

Anway, back to the point, here's the jQuery lightbox plugin:

http://leandrovieira.com/projects/jquery/lightbox/

I've found it to be nicely reliable across browsers, and it "feels" lightweight, requiring minimal mucking around the in the CSS to get it working and to style it (though I've gotta say I haven't had much need to actually mod it's styling). FYI, we almost always use a CSS reset file (usually the YUI one, but sometimes just a plain old * reset for setting padding and margins to 0) and this has played very nicely with that.

If you need to fade a set of images in and out of each other, all in the same box, this jQuery slide show animation plugin might do the trick for you:

http://www.gruppo4.com/~tobia/cross-slide.shtml

This can give you some of the nice fades and transitions that used to be found mostly in Flash-based solutions. The example there are nice, but you also can have a lot of control over how the animations look (think Ken Burns effect, with panning, zooming and fading all going on at once).

I fired this thing up in IE6 to see if it would pass muster and the examples worked. Kudo's to the author (Tobia Conforto) for that. This is a nice plugin to remember when you want to put in some nice self-contained image gallery animations.

If you're in the market for something for this, you might also want to take a look at the jQuery Cycle Plugin, which I've noticed is well supported in the jquery Google group (and I've used it for a few things, with success).