Picture Resize Genius's installer is less than 2 MB, so you won't have to worry about your disk space. Also, the installing process is very intuitive. You have the option of placing a shortcut of the application on your desktop, in the Quick launch bar, or both making it easily accessible. Picture Resize Genius provides a very easy to use interface, by placing all the available actions and features on a side bar and grouping them into three major categories: Files, Actions and Tools.
The first step in running the program is the selection of the images that you want to process. You can do that either by manually choosing the files to load or by opening an entire folder on your disk. Surely, when you add a folder to the image list, only the recognized image formats will be loaded into your processing list. You can, of course, remove any of the images from the list by selecting it and choosing the 'Remove Selected' feature or clear the list of pictures with 'Remove all'.
In the bottom left corner of the application, you can permanently see the number of files in your current image list. All these files will be processed by Picture Resize Genius according to the custom options you define.