How can I regenerate .thumbnails folder in DCIM

I accidentally deleted the contents of .thumbnails folder in DCIM in sdcard. After deleting it I am unable to access MediaStore.Images.Thumbnails._ID however MediaStore.Images.Media.DATA is having all the images. How do I regenerate thumbnails in the .thumbnails folder to get the details of MediaStore.Images.Thumbnails._ID? I initially had the idea that the gallery app in Android generates thumbnails in the .thumbnails folder so what I did was clear the cache of gallery app. Unmounted the sdcard and mounted it again in the hope that .thumbnail folder will have all the thumbnails when I relaunch the app I am using HTC One V(Android version 4.0)