To answer your questions,
1.) Windows 7.
2.) That is exactly what happened. Changing the default program does not work for windows 7 until I had uninstalled Spriter Essentials first then changed the default program because recognizes that the filename is the same and ignores the change in filepath.
3.) There are no bones in this particular project, only sprite images.
4.) The largest image is 39x257.
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