If you want edit-rights, please send me a PN with the desired user name and a valid email address.
In order to overwrite an image, just reupload another file with the same name. All images and other media is managed on this special page: http://wiki.flowergame.net/de/start?do=media
Also please only embed flower images from the flowers namespace (http://wiki.flowergame.net/de/start?ns=flowers&do=media), do not use the existing graphics from the de or en namespaces as they will be removed for being duplicate content. Please neither attempt to upload any new graphics to the flower namespace, it's locked.
(To be honest, I'm not exactly happy with the current wiki. It lacks a lot of useful features )