those all look like they are broken jpegs.

take a jpeg. change a single bit in the file. save it. re-open saved file. see if it broke in a good way*. repeat.

* there's no guarantee for this, the change could be trivial or may break the file so that it doesn't register as a valid jpeg anymore. and the aesthetic values of the result aren't really something you can code a check for.

Right direction: go to Processing.org, use the search box from there... There were several threads about this in the past.