The best open source alternative to WinISO is ImDisk Toolkit, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 10 alternatives to WinISO and three of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to WinISO are Iso Master (Free, Open Source) and xorriso (Free, Open Source).
xorriso itself is entirely controlled by text commands.In dialog mode, xorriso reads them as text lines from standard input. Together with some helpful xorriso commands,it is quite easy for frontend programs to operate a separate xorriso process.