Image Resizer
Resize images to exact dimensions — lock aspect ratio, choose output format
How to Use the Image Resizer
- Upload an image (drag-drop or click).
- Choose a resize mode: Exact Size, By Percentage, Max Dimension, or Crop & Zoom.
- Select output format (PNG/JPEG/WebP) and quality.
- Click Resize to process.
- Download the result.
Multi-step downscaling produces sharp results. All processing runs locally in your browser.
What is Image Resizing?
The Image Resizer allows you to resize, scale, and compress images directly in your browser. You can resize by exact pixel width and height, by percentage scale, or fit within specific aspect ratios while preserving image clarity. Supporting JPG, PNG, and WebP, it provides instant client-side processing without uploading files.
Common Uses
- Optimizing banner images and photos for faster website load times and improved Core Web Vitals
- Resizing product photos to uniform dimensions for e-commerce catalog galleries
- Preparing profile avatars, thumbnails, and social media image uploads
- Downscaling large DSLR and smartphone photos to reduce email attachment sizes
Frequently Asked Questions
Does resizing reduce image quality?
Downscaling (reducing dimensions) retains high sharpness using bicubic interpolation. You can also adjust output quality settings (0-100%) to balance file size against visual fidelity.
How do I maintain the original aspect ratio?
Keep the 'Lock Aspect Ratio' toggle enabled. Entering a new width will automatically calculate the proportional height, preventing image distortion or stretching.
Is there a file size limit?
Because processing happens directly on your device using HTML5 Canvas, file size limits depend on your computer's RAM, easily supporting images up to 50MB.
Notes from this implementation
Pixels in each axis
Resizing redraws the bitmap at a new width and height on a canvas. Aspect ratio is your problem if you set both dimensions without a lock: the picture will stretch. A smaller size throws pixels away. You cannot resize back up and recover them. A larger size invents pixels by interpolation, which looks soft.
Resize before you convert to JPEG if you want a small photo. Resize after you convert if you need a specific pixel count for an upload form. EXIF orientation is a separate issue. Phone photos are often stored rotated with a flag, and a canvas draw that ignores the flag produces a sideways result. If the output is sideways, the source had an orientation tag this draw did not apply.