Size for logo ?

I haven’t found any information about the logo size.
I try to pickup a picture in my gallery but after disconnection, impossible to reconnect.
I’ve an error message in the popup windows due to a large picture…
but impossible to reconnect to access to admin and change it.

My last solution to access again to my site :
– remove hardly the plugin files and the and the parameters in the data base.
– re-install plugin (without a logo…)

http://wordpress.org/plugins/browserid/