Yikes! Pretty hard to get a good view matey as the picture is pretty blury. But if you are using composite, you'll have three RCA leads Red and White which are audio (Left and Right) channels and Yellow (Video). You want to plug these into a "Composite In" port set on the back of your TV. The SAME Composite In. Your three composite leads should clearly indicate which of the 2 leads are the audio ones.
Hope that helps mate!
EDIT: Actually, your first pic gives me something to work with. Here is a PIC of how you should plug your GC composite leads into your TV. NB - NOTE THAT THEY ALL GO INTO ONLY ONE AV IN POST SET (in this case AV 1).
You'll need, of course, to go into the setup-connections settings and define and name your Gamecube as connected to Component AV1.