Version:           0.8.6 (using KDE Devel)
Installed from:    Compiled sources
Compiler:          gcc version 3.4.3  (Gentoo Linux 3.4.3, ssp-3.4.3-0, pie-8.7.6.6) Reading specs from /usr/lib/gcc/x86_64-pc-linux-gnu/3.4.3/specs
Configured with: /var/tmp/portage/gcc-3.4.3/work/gcc-3.4.3/configure --enable-version-specific-runtime-libs --prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/3.4.3 --includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/3.4.3/include --datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/3.4 --mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/3.4/man --infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/3.4/info --with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/3.4.3/include/g++-v3 --host=x86_64-pc-linux-gnu --disable-altivec --enable-nls --without-included-gettext --enable-__cxa_atexit --enable-clocale=gnu--with-system-zlib --disable-checking --disable-werror --disable-libunwind-exceptions --enable-shared --enable-threads=posix --enable-multilib --disable-libgcj --enable-languages=c,c++,f77
Thread model: posix
OS:                Linux

The thumbnail and preview for jpg pictures directly downloaded from a canon EOS Mark II and an Exilim z30 digital cameras are not displayed.
The picture full view works fine.
If the picture is saved after loading into kuickshow even unchanged and under the same name then the thumbnail and the preview are correctly displayed.
However in this case the original EXIF info are lost !!! 
I have two gentoo systems on my opteron based workstation.
One compiled in 32 bits using a Gentoo Linux 2.6.8-r7 kernel and kde 3.3.1 the other compiled in 64 bits usinga Gentoo Linux 2.6.9-r6 kernel using KDE 3.3.1 as well. Both have the same issue.
The issue is not only affecting kuickshow 0.8.6 but also kview 3.3.1, kphotobook 0.0.6, showimg 0.9.3.
When I emerge the KDE application the configure script is issuing "kde need -ljpg : no"
This is no error message at all.
If needed i can provide pictures to reproduce the bug.
I use the following package.keywords file:
x11-themes/gkrellm-themes ~amd64
#
#net-print/hpoj ~amd64
net-p2p/amule ~amd64
net-print/cups ~amd64
net-p2p/azureus-bin ~amd64
net-firewall/guarddog ~x86
net-print/hpijs ~amd64
#
app-cdr/cdrdao ~amd64
sys-fs/mtools ~amd64
#
kde-base/kde ~amd64
kde-base/kdepim ~amd64
kde-base/kdelibs ~amd64
kde-base/arts ~amd64
kde-base/kdegraphics ~amd64
kde-base/kdebase ~amd64
kde-base/kdeadmin ~amd64
kde-base/kdewebdev ~amd64
kde-base/kdeutils ~amd64
kde-base/kdeartwork ~amd64
kde-base/kdenetwork ~amd64
kde-base/kdetoys ~amd64
kde-base/kdeaddons ~amd64
kde-base/kdemultimedia ~amd64
kde-base/kdeedu ~amd64
kde-base/kdegames ~amd64
kde-base/kdeaccessibility ~amd64
#
sys-kernel/gentoo-dev-sources ~amd64
media-video/nvidia-kernel  ~amd64
media-video/nvidia-glx  ~amd64
media-video/nvidia-settings  ~amd64
app-emulation/emul-linux-x86-nvidia ~amd64
sys-apps/hotplug ~amd64
sys-apps/ivman ~amd64
sys-apps/hal ~amd64
sys-apps/dbus ~amd64
dev-python/pyrex ~amd64
media-gfx/imgseek ~amd64
dev-python/imaging ~amd64

My make.conf is the following:

# These settings were set by the catalyst build script that automatically built this stage
# Please consult /etc/make.conf.example for a more detailed example
CFLAGS="-O3 -march=k8 -fomit-frame-pointer -pipe"
CHOST="x86_64-pc-linux-gnu"
CXXFLAGS="${CFLAGS}"
MAKEOPTS="-j4"
USE="multilib -gnome alsa cdr div4linux dvd dvdr exif gphoto2 joystick jpeg mpeg oggvorbis pdflib samba scanner usb videos xinerama xvid -oss cups imagemagick java lcms mad mng msn gpm nocardbus -pcmcia pda png quicktime svga tiff truetype videos wfm wxwindows xine xpm xv" 
CCACHE_SIZE="4G"
LINGUAS="fr"
GENTOO_MIRRORS="ftp://mirror.averse.net/pub/gentoo http://mirror.averse.net/pub/gentoo/ http://www.zentek-international.com/mirrors/gentoo/"

Feel free to contact me if nedeed.