using (var bmp = ImageResizer.DecodeSampledBitmapFromResource (Resources,
    Resource.Drawable.exampleImage, Resources.DisplayMetrics.WidthPixels / 2,
    (int)((Resources.DisplayMetrics.WidthPixels / 2) * _aspect)))
{
    _btnFoo.SetImageBitmap (bmp);
    bmp.Dispose ();
}

public static class ImageResizer
{
    public static int CalculateInSampleSize(BitmapFactory.Options options,
        int reqWidth, int reqHeight)
    {
        // Raw height and width of image
        var height = (float)options.OutHeight;
        var width = (float)options.OutWidth;
        var inSampleSize = 1D;
        if (height > reqHeight || width > reqWidth)
        {
            inSampleSize = width > height
            ? height/reqHeight
            : width/reqWidth;
        }
        return (int) inSampleSize;
    }

    public static Bitmap DecodeSampledBitmapFromResource(Resources res, int resId,
        int reqWidth, int reqHeight)
    {
        var options = new BitmapFactory.Options {
            InJustDecodeBounds = true,
        };

        using (var dispose = BitmapFactory.DecodeResource(res, resId, options)) {
        }

        options.InSampleSize = CalculateInSampleSize(options, reqWidth, reqHeight);
        options.InJustDecodeBounds = false;
        return BitmapFactory.DecodeResource(res, resId, options);
    }
}

I/dalvikvm-heap(  312): Clamp target GC heap from 132.902MB to 128.000MB
D/dalvikvm(  312): GC_FOR_ALLOC freed 1852K, 4% free 126271K/130904K, paused 25ms, total 25ms
I/dalvikvm-heap(  312): Forcing collection of SoftReferences for 3134212-byte allocation
I/dalvikvm-heap(  312): Clamp target GC heap from 132.894MB to 128.000MB
D/dalvikvm(  312): GC_BEFORE_OOM freed 10K, 4% free 126261K/130904K, paused 29ms, total 29ms
E/dalvikvm-heap(  312): Out of memory on a 3134212-byte allocation.
I/dalvikvm(  312): "main" prio=5 tid=1 RUNNABLE
I/dalvikvm(  312):   | group="main" sCount=0 dsCount=0 obj=0x413eeb38 self=0x413ddd78
I/dalvikvm(  312):   | sysTid=312 nice=0 sched=0/0 cgrp=apps handle=1074968028
I/dalvikvm(  312):   | state=R schedstat=( 0 0 0 ) utm=246 stm=59 core=2
I/dalvikvm(  312):   at android.graphics.BitmapFactory.nativeDecodeAsset(Native Method)
I/dalvikvm(  312):   at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:596)
I/dalvikvm(  312):   at android.graphics.BitmapFactory.decodeResourceStream(BitmapFactory.java:444)
I/dalvikvm(  312):   at android.graphics.BitmapFactory.decodeResource(BitmapFactory.java:472)
I/dalvikvm(  312):   at guild.android.screens.CouponItemScreen.n_onTouch(Native Method)
I/dalvikvm(  312):   at guild.android.screens.CouponItemScreen.onTouch(CouponItemScreen.java:47)
I/dalvikvm(  312):   at android.view.View.dispatchTouchEvent(View.java:7495)
I/dalvikvm(  312):   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2291)
I/dalvikvm(  312):   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1985)
I/dalvikvm(  312):   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2291)
I/dalvikvm(  312):   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1985)
I/dalvikvm(  312):   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2291)
I/dalvikvm(  312):   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1985)
I/dalvikvm(  312):   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2291)
I/dalvikvm(  312):   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1985)
I/dalvikvm(  312):   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2291)
I/dalvikvm(  312):   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1985)
I/dalvikvm(  312):   at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2240)
I/dalvikvm(  312):   at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1535)
I/dalvikvm(  312):   at android.app.Activity.dispatchTouchEvent(Activity.java:2466)
I/dalvikvm(  312):   at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2188)
I/dalvikvm(  312):   at android.view.View.dispatchPointerEvent(View.java:7689)
I/dalvikvm(  312):   at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3794)
I/dalvikvm(  312):   at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3678)
I/dalvikvm(  312):   at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4916)
I/dalvikvm(  312):   at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4895)
I/dalvikvm(  312):   at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4993)
I/dalvikvm(  312):   at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185)
I/dalvikvm(  312):   at android.os.MessageQueue.nativePollOnce(Native Method)
I/dalvikvm(  312):   at android.os.MessageQueue.next(MessageQueue.java:125)
I/dalvikvm(  312):   at android.os.Looper.loop(Looper.java:124)
I/dalvikvm(  312):   at android.app.ActivityThread.main(ActivityThread.java:5279)
I/dalvikvm(  312):   at java.lang.reflect.Method.invokeNative(Native Method)
I/dalvikvm(  312):   at java.lang.reflect.Method.invoke(Method.java:511)
I/dalvikvm(  312):   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
I/dalvikvm(  312):   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
I/dalvikvm(  312):   at dalvik.system.NativeStart.main(Native Method)
I/dalvikvm(  312):
D/skia    (  312): --- allocation failed for scaled bitmap
D/dalvikvm(15696): GC_CONCURRENT freed 2085K, 39% free 14681K/23884K, paused 2ms+13ms, total 40ms

android:largeHeap="true"