I have just ran some tests on my local test board (unmodified) and only the posts made by an ignored user will not show (instead a placeholder stating that you are ignoring the member). Threads (started by the ignored user) however will show as normal. So this is standard vBulletin behaviour.
We do require english to be used in all posts on vbulletin.org. Requiring that screenshots (or even modifications) are also in english, is 1 step too far i think.
Well, you have to understand that must of the users aren't english speaker and that they perfer to share their modification for those who speak their same language.