Downloading files with Firefox can get pretty tedious when you want to sort files into different folders, for example image files (JPG/GIF/PNG) to images folder, MP3 files to music folders and so on.
A new experimental extension called Automatic Save Folder, by automatically opening the right folder you want to save the file type in based on the filters you set.
Once you have installed the extensions, you can go to Tools > Automatic Save Folder and setup the filters for the file types, and the folders where they should be saved.
The filters can set based on domain names as well as file extensions or filenames. This is a recommended add-on if you are not yet using a free download manager to manage downloads and want to save some time while saving files in Firefox.