ToolBox Image is a free online image compression tool that operates entirely within the user's browser. Its primary function is to compress, resize, and convert image files, including JPG, PNG, WebP, and AVIF formats, without requiring any uploads to an external server. The tool processes all data locally on the user's device, ensuring that no images are transmitted over the internet. No sign-up, account creation, or file size limits are imposed. The tool offers a range of features designed for quick and private image processing. Users can drag and drop files, browse for folders, or paste images from the clipboard. Batch processing is supported, allowing up to 200 files to be compressed simultaneously. Additional capabilities include format conversion, rotation by 90 or 180 degrees, and adjustable quality levels. A side-by-side comparison slider lets users preview the compressed image against the original before downloading. Output options include downloading individual files or saving all processed images as a zip archive. The compression is powered by WebAssembly (WASM) technology, enabling typical processing times of under one second per image. Typical use cases include reducing image file sizes for email attachments (under 25 MB), meeting Discord's upload limit (under 8 MB), or achieving a specific target file size (e.g., 100 KB). The tool is also suitable for general image optimization for web use or storage. The workflow is straightforward: drop or paste an image, select a target quality, size, or output format, compare the result with the original, and then download or batch save. The tool is designed for users who prioritize privacy and speed, with no requirement for software installation or internet connectivity beyond the initial page load.