Trout is a mind mapping app that allows you to rapidly associate ideas and help you organise your ideas in a non-linear way.
You can use images on your mind map. Drag from Photos or Finder
You are not restricted from cross linking your nodes and links may be labelled.
The UI is keyboard oriented and can be used on a laptop without mousing which makes it ideal for lectures and seminars.
You can also work with your mind maps on the iPad version.