Your images will be presented in the order in which they’re displayed in Bridge. If you’d rather use a different order, change the order in Bridge.
In Adobe Bridge, choose Tools > Photoshop > Web Photo Gallery.
In Photoshop, choose File > Automate > Web Photo Gallery.
A home page for your gallery named index.htm or index.html, depending on the Extension options. Open this file in any web browser to preview your gallery.
JPEG images inside an images subfolder.
HTML pages inside a pages subfolder.
JPEG thumbnail images inside a thumbnails subfolder.