objective c - How to pick the Path Asset in a existing image with ALAssetsLibrary? -

i have code write / create new image in ios photo library:

alassetslibrary *library = [[alassetslibrary alloc] init];     // request save image camera roll     [library writeimagetosavedphotosalbum:[imagem cgimage] orientation:(alassetorientation)[imagem imageorientation] completionblock:^(nsurl *asseturl, nserror *error){  //code here...  } 

the code this, stamped in code writeimagetosavedphotosalbum, in time don`t need create new image in library, need path of image exist in library, in case image inside variable 'imagem'.

what code change writeimagetosavedphotosalbum path of image?

[edit]

i image inside variable imagem in format:

-(void)imagepickercontroller:(uiimagepickercontroller *)picker didfinishpickingmediawithinfo:(nsdictionary *)info{      uiimage *imagem  = [info objectforkey:uiimagepickercontrolleroriginalimage];     [imagepicker dismissviewcontrolleranimated:yes completion:nil]; } 

you have:

-(void)imagepickercontroller:(uiimagepickercontroller *)picker          didfinishpickingmediawithinfo:(nsdictionary *)info{     uiimage *imagem  = [info objectforkey: uiimagepickercontrolleroriginalimage]; } 

but don't need image; need path. be:

-(void)imagepickercontroller:(uiimagepickercontroller *)picker          didfinishpickingmediawithinfo:(nsdictionary *)info{     nsurl *imageurl  = [info objectforkey: uiimagepickercontrollerreferenceurl]; } 

now have url , can store it; can retrieve actual image later if need it.

to asset url image, see answer here: https://stackoverflow.com/a/22968941/341994