I receive a lot of messages and notifications from a lot of wikis. So i don't really read them or pay attention to them.
Then, about these images, I rarely work with jpg cos I do think their quality is not that good. The problem is not having a larger pic. It is to have good looking pics on the articles, and only png are cool for that. So, personally I'll just continue to work with png :) I prefer the quality over the easiness ^^ But if you think jpg are better, feel free to continue; everyone has its opinion on the topic ^^