Top Alternatives to RIOT - Radical Image Optimization Tool

ImageOptim is a powerful macOS utility designed to significantly reduce the file size of images without compromising visual quality. It achieves this by intelligently removing unnecessary metadata and employing various compression techniques, resulting in faster website loading times and reduced storage requirements.

XnConvert is a robust and free cross-platform batch image processing tool designed to handle multiple image manipulation tasks at once. It supports over 500 file formats and allows users to combine more than 80 distinct actions, making it an indispensable asset for photographers, graphic designers, and anyone requiring efficient bulk image editing.

PNGGauntlet is a free Windows application designed to optimize PNG images, making their file sizes significantly smaller without any loss in quality. It achieves this by combining prominent compression tools like PNGOUT, OptiPNG, and AdvPNG into a user-friendly interface.

FastStone Photo Resizer is a free batch image converter and renaming tool designed for efficiency. It handles various image formats and offers essential editing functions like resizing, cropping, watermarking, and color adjustments in a batch process.

Image Tuner is a comprehensive free batch image processing tool for Windows, offering effortless resizing, renaming, format conversion, and watermarking of multiple images simultaneously. It supports various image formats and integrates seamlessly with Windows Explorer for convenience.

Light Image Resizer is a comprehensive yet easy-to-use application for resizing, converting, protecting, and organizing your digital photos and images. It supports batch processing, allowing you to optimize large collections quickly.