This example webbot relies on a library called
LIB_download_images, which is available from this book's website. This library contains the following functions:
download_binary_file(), which safely downloads image files
mkpath(), which makes directory structures on your hard drive
download_images_for_page(), which downloads all the images on a page
Figure 8-2. Re-creating a file structure for stored images
For clarity, I will break down this library into highlights and accompanying explanations.