I install both Screenshot Captor and ZUploader in portable  mode.
How do I config Screenshot Captor to use ZUploader?
I search all .ini files and can't find anything relative to it.
It seems that Screenshot Captor  is search for registry data for ZUploader path.

I downloaded the DCDisplay. But when it ask to install .net framework 4.0, I stop. Sorry.

This test benchmarks the average decoding time to goto next image file.
Machine Hardware: Thinkpad T42 1.5 GHz Dothon CPU(2MB cache), ATI Mobility Radeon 9000
Test Method: Browser through 9 jpeg files with 1200MP.
                   When the image is completely decoded, pagedown to the next file.

   ACDSee Pro 2.5                   0.50
   FastPictureViewer 1.0 build 109  0.55 (GPU Acceleration is not supported on my machine)
   Hamana 1.48                      0.83
   JPEGView  1.0.21.0               0.94
   ColorStorm 10.9.8.11             1.07
   MangaMeeyaCE  2.4 Beta           1.23
   Picasa 3.8                       1.37
   FastStone  4.2                   1.43
   MaxView 2.4                      1.43
   Fax&Image  (xp)                  1.46
   XnView 1.97.8                    1.54
   FastStone  3.8                   1.56
   XnViewMP 0.32 beta (Dec 6 2010)  1.57
   IrfanView   4.28                 1.57
   Imagine 1.0.8 WIP(Jul 5 2010)    1.70

Conclusion:
ACDSee Pro is still the King of speed. The commercial software has its selling point.
But I would like to see how fast FastPictureViewer is with GPU acceleration.

Hamana is designed for reading comics.

JPEGView is the one I recommend, fast, free and open source.
Unicode filenames and directories are no problem.
It also support some photo editing features, and can show EXIF data on top of photos.
The only features I missed are color manager, and lossless crop.