the nano cubes (or like systems) do have closed lids
a closed system like this can affect the waters ability to perform gas exchange. the use of a
skimmer or something usually really helps that out. in the case of these nano cubes, the filtration in the back actually works quite well to aerate the water.
so in short, if you are doing a simple glass tank you will want to keep an eye on it, although as im sure you know a tank this small will likely need water changes every few days, that might actually server you ok on the gas exchange
as far as pictures, i cant help much there, my smallest tank is a 29 gl, but i do wish you all the luck , these nano or pico (in this case) tanks can be quite a challenge..
