Online image gallery from local folder structure??

Does anyone know of a program (ideally for the Mac, but it can also be for Windows) that will allow me to create (and possibly sync) an online web gallery from a specified folder structure of images stored locally on my computer?

iPhoto 'sort of' allows this capability, but one thing that I am after is the ability to customize the appearance of the web gallery, which iPhoto does not allow. Not to mention the fact that iPhoto would 'sort of' allow this capability so long as your images reside within the iPhoto Library...

Here's a breakdown of the solution I was hoping to find:

• I could specify the path of a folder of images (which would contain multiple levels of sub-folders)
• Images within this folder and it's sub-folders would then be dynamically converted using predetermined dimensions, file format, compression level, etc...
• Then a custom or bundled template would then be used to create the web gallery.
• Finally the resulting gallery would be uploaded to a specified location of my choosing and made available online.
• Bonus ~ subsequent changes to any locally stored image would result in the program automatically updating the out-of-date versions of the image online, replacing it with the newly modified version.

Perhaps such a program doesn't exist (it does almost sound to good to be true), but I figured it couldn't hurt to ask in case one does that someone might be able to share with me...

Any suggestions would be greatly appreciated... Thanks!