The idea is good, indeed.
However, there is a problem: you won't store the picture in the blockchain (even if it's the Ubiq blockchain, it doesn't matter). So maybe a link to a centralised server or something like this?
Maybe it would be easier to give the possibility to add a little text, so this portugalian can either write "Big up to portugalian football team" (or whatever he wants) or put a link of something, for example an image (of the flag, you got it).
I don't really know the technical limitations of this but since we can't store huge amounts of data in a blockchain, I think it would be a better idea.
PS: but you're right, it could be pretty funny.
Ubiq is a best community fork of Ethereum. Since that it uses Solidity as smart contracts language. Solidity allows to use hashes inside the contracts and it allows to store arrays of string data. Respectively it can store links to centralised storages and text information. If GeoCoin contract written properly so then it should allow have API which allows to connect with external modules and extensions. One of that external module can store all additional data, so it will not reduce GeoCoin tokes transaction speed and will allow to add such feature.
That is one of the benefits of migration from original Bitcoin fork blockchain to a Ubiq blockchain based on smart contracts allowing us to create more complex applications. If more applications and extensions will be created based on Geo API then project will more be intresting and useful.