Free Image Resizer - Resize Images Online
Resize your images instantly with custom dimensions, percentage scaling, or one-click social media presets. Choose your output format and quality. Completely free, private, and processed entirely in your browser.
100% client-side - your images never leave your device
Resize Image
Drag & drop your image here
or click to browse - supports PNG, JPEG, WebP, GIF, BMP (max 50 MB)
How to Resize an Image
Upload Your Image
Drag and drop an image into the upload zone, or click to browse your files. Supports PNG, JPEG, WebP, GIF, and BMP formats up to 50 MB.
Set Target Size
Choose custom pixel dimensions with aspect ratio lock, scale by percentage (10%-500%), or select from popular social media presets like Instagram, Facebook, or YouTube.
Download Resized Image
Pick your output format (PNG, JPEG, or WebP), adjust quality for JPEG/WebP, then click Resize and download your perfectly sized image.
How Image Resizing Works
new_height = original_height x (new_width / original_width)Image resizing works by resampling the original pixel grid onto a new grid with different dimensions. The browser's Canvas API handles the interpolation, using bicubic smoothing to produce clean results.
Aspect ratio = width / heightPixels = width x heightScale factor = new_dimension / original_dimensionKey concepts in image resizing:
- Aspect ratio preservation - Maintaining the width-to-height ratio prevents images from appearing distorted. When locked, changing one dimension automatically calculates the other.
- Downscaling vs. upscaling - Reducing image size generally preserves quality because pixels are combined. Enlarging creates new pixels through interpolation, which can introduce softness.
- Output format and quality - PNG is lossless (best for graphics with sharp edges), JPEG uses lossy compression (best for photographs), and WebP provides the best balance of quality and file size.
This tool processes everything locally using the HTML5 Canvas API. Your image is drawn onto an invisible canvas at the target dimensions, then exported as a blob for download. No server round-trip means instant results and complete privacy.
Frequently Asked Questions
Is my image uploaded to a server?
No. This image resizer works 100% in your browser using the HTML5 Canvas API. Your images never leave your device, making this tool completely private and secure. No data is transmitted to any server.
What image formats are supported?
You can upload PNG, JPEG, WebP, GIF, and BMP images. For output, you can choose between PNG (lossless), JPEG (smaller file size with quality control), or WebP (best compression with quality control). You can also keep the original format.
How does the aspect ratio lock work?
When the aspect ratio lock is enabled (on by default), changing the width automatically calculates the correct height to maintain the original proportions, and vice versa. This prevents your image from appearing stretched or squished.
What is the maximum image size I can resize?
You can upload images up to 50 MB. Since all processing happens in your browser, very large images (such as 4K or higher resolution) may take a moment to process depending on your device performance.
How do the social media presets work?
The presets provide one-click sizing for popular social media platforms. For example, selecting "Instagram Post" automatically sets the dimensions to 1080x1080 pixels, the recommended size for Instagram square posts. This saves you from having to look up the correct dimensions.
Does resizing reduce image quality?
Enlarging an image beyond its original dimensions can reduce apparent quality because new pixels must be interpolated. Reducing image size generally preserves quality well. For JPEG and WebP output, you can control the compression quality with the quality slider (higher values mean better quality but larger files).
Privacy First
This image resizer processes everything directly in your browser using the Canvas API. Your images are never uploaded to any server, stored, or transmitted over the network. All processing happens locally on your device for complete privacy and instant results.