Add empty space to the image
============================

Add 2Gb

> dd if=/dev/zero bs=1024k count=2048 >> 2014-09-09-wheezy-raspbian.img

Expand partition size
=====================

> fdisk 2014-09-09-wheezy-raspbian.img

Command (m for help): *p*

Disk 2013-02-09-wheezy-raspbian.img: 4087 MB, 4087349248 bytes
255 heads, 63 sectors/track, 496 cylinders, total 7983104 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00014d34

                         Device Boot      Start         End      Blocks   Id  System
2013-02-09-wheezy-raspbian.img1            8192      122879       57344    c  W95 FAT32 (LBA)
2013-02-09-wheezy-raspbian.img2          *122880*     3788799     1832960   83  Linux

Command (m for help): *d*
Partition number (1-4): *2*

Command (m for help): *n*
Partition type:
   p   primary (1 primary, 0 extended, 3 free)
   e   extended
Select (default p):
Partition number (1-4, default 2):
First sector (2048-7983103, default 2048): *122880*
Last sector, +sectors or +size{K,M,G} (122880-7983103, default 7983103):
Using default value 7983103

Command (m for help): *w*
The partition table has been altered!

Syncing disks.

Resize partition
================

> df | grep /mnt/arm

/dev/loop0                3927752   1955672   1794172  53% /mnt/arm_rPi
/dev/loop1                  57288     18960     38328  34% /mnt/arm_rPi/boot

sudo resize2fs /dev/loop0