Questions and postings pertaining to the usage of ImageMagick regardless of the interface. This includes the command-line utilities, as well as the C and C++ APIs. Usage questions are like "How do I use ImageMagick to create drop shadows?".
The mogrify command will resize each image in one directory -- one output for each input in the directory. So you would likely need to write a script to loop over each directory and use mogrify. Alternately, you would have to write a script to loop over each image in each directory and use the convert command. Perhaps one of the Windows users can give you better pointers. But Imagemagick by itself does not deal with recursive directories.