XnConvert is a powerful and free cross-platform batch image processor, allowing you to combine over 80 actions. Developed by XnView
License: Free
XnConvert is a more feature-rich tool that excels in extensive editing options and format support, making it ideal for advanced users and large projects. FastStone Photo Resizer, on the other hand, offers a faster, simpler solution for basic image processing tasks, catering more to casual users.