This question is linked with the answers in the following question:
Error removing Bitmaps[Android]
Is there any advantage of using Drawable over Bitmap in A
Acc. to this page, starting from API Level 11, the Bitmap pixel data is stored in the Dalvik Heap along with the associated Bitmap. Thus calling .recycle is actually not required, unless you want to reclaim the memory manually for further use. Be sure to de-reference the bitmap too, just as an added measure.
PS: This was the link which explains hackbod's answer.