cannot set bmp as desktop background (and no reason given)

* right-click on the desktop
* select "change desktop background"
* click on the "+" sign on the bottom
* browse and select some bmp file

expected: the file should appear on the left and you should be able to select it as a background (this happens with jpg files)

observed: the file browser closes but the file is not added. No error message is given

If the bmp file format is not supported (which I don't see why it shouldn't be) or if anything is wrong with the file itself, an error message should be given.

I attach a bmp file that exhibits the issue just in case it's this file in particular

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: unity 4.28.0-0ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-16.28-generic 3.0.17
Uname: Linux 3.0.0-16-generic i686
NonfreeKernelModules: nvidia
.proc.driver.nvidia.gpus.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0'
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86 Kernel Module 280.13 Wed Jul 27 16:55:43 PDT 2011
 GCC version: gcc version 4.6.1 (Ubuntu/Linaro 4.6.1-9ubuntu3)
.tmp.unity.support.test.0:

ApportVersion: 1.23-0ubuntu4
Architecture: i386
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
Date: Sun Feb 5 21:08:14 2012
DistUpgraded: Log time: 2011-12-07 19:34:40.350850
DistroCodename: oneiric
DistroVariant: ubuntu
GraphicsCard:
 nVidia Corporation G84 [GeForce 9500M GS] [10de:0405] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: ASUSTeK Computer Inc. Device [1043:15d2]
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100429)
JockeyStatus:
 xorg:nvidia_173 - NVIDIA accelerated graphics driver (Proprietary, Disabled, Not in use)
 xorg:nvidia_173_updates - NVIDIA accelerated graphics driver (post-release updates) (Proprietary, Disabled, Not in use)
 xorg:nvidia_current - NVIDIA accelerated graphics driver (Proprietary, Enabled, In use)
 pkg:sl-modem-daemon - Software modem (Proprietary, Disabled, Not in use)
 xorg:nvidia_current_updates - NVIDIA accelerated graphics driver (post-release updates) (Proprietary, Disabled, Not in use)
MachineType: ASUSTeK Computer Inc. M51Sn
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.0.0-16-generic root=UUID=173acbf5-26a0-49e3-8d2b-f1c142582cbf ro quiet splash vt.handoff=7
SourcePackage: unity
UpgradeStatus: Upgraded to oneiric on 2011-12-07 (59 days ago)
dmi.bios.date: 12/24/2007
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 303
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: M51Sn
dmi.board.vendor: ASUSTeK Computer Inc.
dmi.board.version: 1.0
dmi.chassis.asset.tag: ATN12345678901234567
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK Computer Inc.
dmi.chassis.version: 1.0
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr303:bd12/24/2007:svnASUSTeKComputerInc.:pnM51Sn:pvr1.0:rvnASUSTeKComputerInc.:rnM51Sn:rvr1.0:cvnASUSTeKComputerInc.:ct10:cvr1.0:
dmi.product.name: M51Sn
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK Computer Inc.
version.compiz: compiz 1:0.9.6+bzr20110929-0ubuntu6.1
version.libdrm2: libdrm2 2.4.26-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 7.11-0ubuntu3
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 7.11-0ubuntu3
version.nvidia-graphics-drivers: nvidia-graphics-drivers N/A
version.xserver-xorg: xserver-xorg 1:7.6+7ubuntu7.1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.6.0-1ubuntu13
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.99~git20110811.g93fc084-0ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.15.901-1ubuntu2.1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110411+8378443-1