I use gallery for my photos at the moment, mainly because someone else installed it on the server.
When adding a large number of photos to gallery at once, you can pre-upload them to your server using whatever method you like, and then tell gallery where you put them.
Gallery then lists each picture it finds in that directory with a tick box next to it, and the ones that you leave ticked are added to the gallery when you click 'Submit'.
The problem with that is if you want to select a subset of photos from that directory (e.g. you are sorting a big pile of photos into categories when you put them into the gallery) you may have to click a huge number of times - often once per photo.
My solution is to use a <select> tag, which lets you define a list, instead of check boxes. You can now use your OS shortcuts for manipulating lists to speed up the process. So, click on the first item, hold shift, click on the last to select a range in Windows, for example.
Patches in the directory above apply to the gallery in Debian stable/woody and Debian unstable/sid as of 23:09 13/12/2004.