If you're looking for a thumbnail based picture browser PhotoAlbum by Helmut Hoffmann is a good option. It can generate thumbnails of images in a directory and optionally sub-directories. You can then browse through them and view the full image in a pop-up window. It is quite configurable and is significantly faster than other similar programs I have tried. I think this is because it has built-in support for many image format rather than relying on datatypes.
I have a button configured in Opus so I can open a PhotoAlbum window showing the images in a directory with one click. Options then allow you to delete images, load them into external programs etc.
PhotoAlbum is shareware and comes with a very nice picture viewer called Cybershow.
You can download demo versions fron the
PhotoAlbum website.
Robert