Javascript - Simulate 'right click=>save as' to save an image on a page to a place on user's computer.

This is a dual question actually.  My purpose is to save all of the images on a page to a specific directory on the user's computer upon request.  I know I have seen in web pages, the ability to click on a button that says 'browse' for instance, and a little Windows explorer window pops up allowing you to navigate to a specific destination on your hard drive.  That is usually to find a file to upload however.  I'm wondering if I can do such a thing to select a directory to save a file to and if it can be done with javascript or what is used to do it.  If not in javascript, then in ASP.NET?  The application is actually an ASP.NET application.  Secondly, I'm wondering if it is possible to use javascript to simulate a left click on an image and saving it to the above mentioned (browsed to) location.  I would like to be able to do all this with just a browse to field and a button to execute the operation.  The user should not need to right click and save.  Once again, I have ASP.NET and javascript to use.  Any suggestions?