What in this code causes memory leak in C#? -

in windows task manager discovered memory usage of program increases on time while it's running. memory leak caused code below. code loop iterating on list of images , resizes them according code example in msdn. resources seem managed , freed .dispose().

foreach ( string file in files ) {     image = image.fromfile( file );      rectangle croprect = new rectangle( 0, 0, 1000, 1000 );     bitmap src = ( bitmap ) image;     bitmap target = new bitmap( croprect.width, croprect.height );      using ( graphics g = graphics.fromimage( target ) )       {         g.drawimage( src, new rectangle( 0, 0, target.width, target.height ),                                         croprect,                                         graphicsunit.pixel );     }      image.dispose();     image = image.fromhbitmap( target.gethbitmap() );     src.dispose();     target.dispose();     image.dispose(); } 

could advise please can cause of memory leak in code?

from docs of gethbitmap:

you responsible calling gdi deleteobject method free memory used gdi bitmap object. more information gdi bitmaps, see bitmaps in windows gdi documentation.

then, docs of fromhbitmap:

the fromhbitmap method makes copy of gdi bitmap; can release incoming gdi bitmap using gdi deleteobject method after creating new image.

seems pretty clear... need call deleteobject:

[dllimport("gdi32.dll")] private static extern bool deleteobject(intptr hobject); 

as sjoshi points out, should use using blocks ensure dispose called in case of exception. deleteobject call should inside finally block same effect.