DirectX: Do I need this?

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I am building a .net app that does some simple image tasks (Tiff
files): viewing Tiff, viewing thumbnails from multipage tiff,
rotation, page (frame) deletion, etc.

The problem is that it is so frustratingly slow. Creating and viewing
thumbnails for a 50-page tiff (scan of text document) takes about 40
seconds. Commercial image viewers do the same thing in a split second.

I read on bobpowell.net that for fast GDI+, you need DirectX 9.0. I
don't know anything about DirectX. Before I spend days/months
tinkering with it, i'd like to know if DirectX is the "ticket" to a
speedy graphics application. By using DirectX, could my application
potentially be lightening fast for doing the tasks i mentioned above?

Also, is DirectX an alternative to GDI+? Or do they work together?

Thanks for your help!

John

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