Joomla robot.txt file - blocked image directory

my horrible mistake

[Yangtze]

After i transformed my whole site to joomla, my ranking lost in all search engines. There could be a number of reasons, last night i checked my Robot.txt

I suspect it is caused by this robot file, here is my reason:

The robot.txt disallowed my /images/ directory !
this comes with default joomla robot.txt

Could this be the reason?

I must done something wrong, otherwise it won't be ALL search engines stopped rank the site high.

Any ideas?

[goodroi]

Whenever you switch your site to a new CMS (joomla, wordpress, pligg, drupal, whatever) you have to be very careful. There are countless potential pitfalls and unfortunately it sounds like you fell into at least one pitfall. Here are the most common pitfalls:
1)rewrites robots.txt to block search engines from all pages
2)add metatags to each page to block search engines
3)add metatags with improper language/location info that limit you to country specific serps
4)break your old link structure
5)rewrite all url addresses

If I were you I would check out the robots.txt, the metatags on your pages and make sure you do not have any 404 errors. If you have any 404 errors you should use a 301 redirect to send them to the new page and if you dont have a new page then create one asap. Good luck.