Get default image directory with styles large? My images are saved in folder 

sites/all/default/files/styles/large/public/field/image


But to make this future save i dont want to hardwire the path? Is there a drupal function to get the images in a proper way? 
I played around with

image_style_url(uri)


But i just need the default dir to pass it to javascript, I dont have image uris yet...

Thanks a lot!
I'm not sure this will get you exactly what you want, but the 'default' path is just public://, so.

$url = image_style_url('large', 'public://');


will return

http://yoursite.com/sites/default/files/styles/large/public


I think it's more likely you're looking for a specific path, e.g.

$url = image_style_url('large', 'public://field/image');


which returns

http://yoursite.com/sites/default/files/styles/large/public/field/image