For example, I love military decorations, and here's Wikipedia's Service Ribbon, how can I download all the ribbon images at once instead of clicking them one by one and then select "Save image as"?
Use OS X's Automator.app to find, extract, and save the images from your current web page. The combination of Actions needed are:
To learn more about using Automator, see Apple's Mac Basics: Automator.
An alternative approach is to use
You can install
You might also just use
Downloading images from Tumblr or Blogspot:
You can use Firefox and Flashgot, which is an extension which does pretty much exactly what you are looking for.
You can find Flashgot on the official Mozilla addons website here
Flashgot uses a download manager of your choice, either the one integrated in Firefox, curl, wget, or others. Personally I like DownThemAll!.