The EU doctor (?) is examining his Greek patient. The patient says, "I don't see how we can tighten our belt much more ...". The doctor replies, "Here, let me show you" as he puts the belt around the man's neck. In fact, the 'belt' turns out to be a dog leash, symbolizing Greece's submission to the 'troika', i.e., the EU, the ECB, and the IMF.
If you have to tighten your belt, you have to spend less money and manage without things because you have less money than you used to have. • In the new economy, we all have to learn to tighten our belts. The saying is from the depression era where there was little money for anything including food, so people had to tighten their belts in order to keep their pants (UK=trousers) from falling down. The cartoonist uses a visual representation of this idiom/metaphor to suggest that, in return for the bailout, Greece will not only have to implement even more drastic austerity measures, but will also have to accept severe restrictions on its financial sovereignty.
Kal has a very similar belt-tightening cartoon in The Economist.
• Greece begrudgingly cedes sovereignty in exchange for bailout funds (Christian Science Monitor)
• Eurozone agrees €130bn bailout for Greece (Daily Telegraph)