It's very strange that Wiki doesn't support JPEG2000 because it's main format for Internet Archive books scans (note that Wikisources using Commons for books scans).
Jan 9 2018
Jul 11 2017
Jun 26 2017
Please! It's really useful not only for Russian but for Ukrainian also. In our languages Church Slavonic texts usually citing in modern texts without additional styling, we distinguish modern text from cites by font only. It's common tradition since beginning on 18 century while modern font (гражданский шрифт) was designed. So now, without these fonts we are not able made adequate copies of many sources in Ukrainian and Russian Wikisources and we do not able made Church Slavonic (i. e. Church and all pre-18 century) cities according to our typographic traditions in Russian, Ukrainian and possible both Belarus Wikipedias.