Automated cover scaling
This tool locks the target dimensions to exactly 3840×2160 pixels (a 16:9 aspect ratio) and forces “cover” mode. It scales your uploaded images proportionally until both dimensions meet or exceed the 4K target, then crops the excess from the center. This guarantees a perfect ultra-HD widescreen frame without any stretching or letterboxing, ideal for 4K monitors and cinematic visuals.
Local batch processing
The entire 4K resizing pipeline runs directly in your browser using a background Web Worker pool. You can drop hundreds of high-resolution images into the queue at once. The tool will process them in parallel without uploading anything to a remote server, keeping your original files private and saving bandwidth.
Output format and downloads
Processed files retain their original format (JPG, PNG, or WebP). The tool appends the 3840×2160 dimensions to the original filename (e.g., photo-3840x2160.jpg). You can download the resized images individually from the list or package the entire batch into a single ZIP archive.