iphone - iOS addSubview & removeFromSuperview causing memory leaks -

i have following issue:

i have 1 instance class extends uiviewcontroller class, in class adding uiimage uiimageview, , adding uiimageview self.view using method "addsubview:" [self.view addsubview:imageview] , adding self.view window using [[[uiapplication sharedapplication] keywindow] addsubview:[self view]] , , when click on close button clearing self.view (removing subview "uiimageview") , removing self.view window.

now issue when using same instance add other uiimageview other image, first data not freed memory have released them , removed them superview. following code illustrates problem.

- (void) setimagewithurl: (nsstring *)url {      nsdata * imagedata =nsdata * imagedata =[nsdata datawithcontentsofurl:[nsurl urlwithstring:url]];      if (imagedata) {             uiimage *image = [[uiimage alloc]initwithdata:imagedata];             [[[uiapplication sharedapplication] keywindow] addsubview:[self view]];             [self createviewwithimage:image];             [image release]; }  -(void) createviewwithimage: (uiimage *) image{     [self.view sethidden:false];      uiimageview *imageview = [[uiimageview alloc] initwithimage:image];      [self.view addsubview:imageview];      [imageview release]; }  // removing imageview when click on close button -(void) closeview{             (uiview *subview in self.view.subviews) {                   [subview removefromsuperview];              }             [self.view removefromsuperview];  } 

note: have used xcode instruments test memory allocation.

update: after more research .. not addsubview & removefromsuperview make memory leaks.. nsdata. dont why not released memory. have made changes test if nsdata, saved image locally , set image using 2 cases:

//case 1: nsstring *path = [[nsbundle mainbundle] pathforresource:@"image" oftype:@"png"]; nsdata * imagedata =[[nsdata datawithcontentsoffile:path]; image = [[uiimage alloc]initwithdata:imagedata];   //case 2:  nsstring *path = [[nsbundle mainbundle] pathforresource:@"image" oftype:@"png"]; image = [[uiimage alloc] initwithcontentsoffile:path]; 

i have found case 1 makes memory leaks, while case 2 clean.

now uiimage cant take image without using nsdata, , reason nsdata not released .. how can fix problem !!!!

do have a:

[super dealloc]; 

in deriving class's dealloc?