Decreasing the size of a full Omicron scan output?

Ciao Florent,

With BruCo, the full Omicron scans have the largest output on disk for the DQR. This is not a surprise -- they are full scans -- but I have a couple of questions.

• Would it be possible to have an option called nothumbnail or alike, that would prevent the pictures th*.png from being generated? The webpage would be heavier to load (as it would display the larger Omicron maps) but the number of files would be reduced by half and the size of the output by about 1/3 -- which would already help a lot.
• What are the criteria used by Omicron to decide whether Omicron maps should be plotted or not for a given channel? Are there some rooms to make those criteria slightly tighter and/or user-defined?