Thumbnails and full size images are not generated

I just installed Omeka 2.0. When uploading an image file, there is no derivative files generated. Thumbnails and fullsize under files folder are empty. How does Omeka generate these files? The only file is in files/original.

Those are generated by using ImageMagick. When you install Omeka, it checks whether it is available on the server, so if no warning came up, Omeka should be generating those.

You might try going to the admin->Settings page, and running the test to see if the path to ImageMagick is correct.