There will be an approval system where real people look at the before, after and proof pictures to judge if someone is gaming the system.
And these real people will be... one of your employee? The citizens themselves? One of the cryptocommunity that happen to be around? One of the member of your project?
The citizens themselves
And these citizen themselves will not take picture because the "picker" ask them to do that, will they? Like, "hey, there are some trash out there, can you take some shoot of it on this condition, while I pick it, and the cleaned ones after I pick them"? Because if that's your concept, then we are going back toy previous question of how will you be sure the trash was not a mere set-up by the cheating picker?
And if your concept is the entirely opposite of the illustration above, you assume that without anyone asked their help to take a photo evidence of trash lying around, the citizen will miraculously have an initiative to do that, then waiting for people to take that, then take another photo of an already cleaned street, the whole scenario will be a little bit twisted, isn't it? Because if they do, then their moral compass need a better calibration. They waited for someone to take the trash instead of cleaning it up themselves. The aim to raise trash awareness is utterly failed on this scenario
We have tested a couple versions of the app already and based on feedback from users, we are updating it to include two methods for people to play the game. Some people have the "moral compass" to be a self-cleaner. We have a feature for them to be rewarded with the Impact Zones. And many people who don't have the time or energy, or desire to be a person who cleanups, they are already regularly reporting trash complaints to the city-- we are adding the picture taking, which has also been successful for other organizations around the world. We have analyzed what it is that keeps certain areas clean and it comes down to money. This is why we have created the coin. We can't rely on do-gooders to to do enough good to stop the trash problem. We want to pay people to do it who need the money-- like the can collectors who are already raiding recycle bins for the redemption program. In NYC, a single redemption location in Brooklyn brings in over half a million USD/year. There is money and reports being made in the system already. Emrals is working to bring it all together with the power of the blockchain.