Media permalinks changed

Hi all,

After i changed server and updated everything in my wordpress, my image links seem to be broken.

First they were in this form: (also the url my website is referring to)
http://kheuning.nl/moustache/wp-content/uploads/2014/04/purple-obelix-copyPURPLE-OBELIX-COPY-600×380.jpg

Now in the media library they are named like this:
http://kheuning.nl/moustache/?attachment_id=2699

How can i change all the permalinks back so that my website works again? I found a forum post that told about a certain option in /wp-admin/options.php but I couldn’t figure it out.

Thank you all very much!

Jonas