After expanding the ScreenShotApps bundle, store the bundled mini-programs on your hard drive, then use Spark to assign each to a keyboard shortcut. I've chosen to use Shift-Command and the number keys. So Shift-Command-1 gets a full screen PICT, -3 is a PDF, -5 is a JPEG, etc. I use -2, -4, and -6 for selected region screenshots in those same formats. As with the built-in screenshot tool, you can add the Space Bar for object capture, or Control to capture to clipboard.
I've explained this all in more detail in this PDF.
[robg adds: taketo's native language is not English, so I've rewritten the above hint based on my understanding of the process from his original submission. I have not done any work on the PDF, however, but it's still quite easy to follow along. The ScreenShotApps site is very slow to load, but it will eventually show up. I haven't tested this myself on 10.4; it worked for the author on 10.3.]

