RealFaviconGenerator:

Master picture is predefined and passed by URL (http://realfavicongenerator.net/demo_favicon.png in this example).

Master picture is predefined and passed directly, encoded in Base64.

No master picture. The user will choose one from RealFaviconGenerator.

None, the choice is left to the user.

Favicon files will be in the root directory of the target web site.

Favicon files will be in another directory.

No callback, the user downloads the favicon files directly from RealFaviconGenerator.

After the favicon creation, the user is redirected to the caller.

Favicon Generator: