About ImageCommand
All command-classes subclass ImageCommand, which itself subclasses org.im4java.process.ProcessStarter. The latter class wraps java.lang.ProcessBuilder, handles input and output streams and supports asynchronous execution.
Custom URL Scheme
WhatsApp provides a custom URL scheme to interact with WhatsApp:
If you have a website and want to open a WhatsApp chat with a pre-filled message, you can use our custom URL scheme to do so. Opening whatsapp://send?text= followed by the text to send, will open WhatsApp, allow the user to choose a contact, and pre-fill the input field with the specified text.