On the Fly JPG to BMP conversion
you forgot :
ImageMagick is the fastest image conversion I've used with more effects, if effects are important.
My vote is IrfanView for the GUI, and ImageMagick for the command line.
Irfanview works great from command line too. Anyway both tools will be more than suitable for that work.
If you're running .NET, I believe you can write the code to this pretty easily.
one more vote for IrfanView.
I embedded ImageMagick in a piece of server software to do on-the-fly image transforms and had not problems with it. It is *very* fast and easy to program.
I use IrfanView also.
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