Image Resizer
Upload an image and resize it to custom dimensions. All processing happens in your browser — your images never leave your device.
Image resizer
Updates as you dragExamples
How It Works
Aspect ratio is the proportional relationship between width and height (e.g. 16:9). Maintaining it during a resize ensures the image is scaled uniformly — otherwise subjects appear stretched or squashed. When you change one dimension with the ratio locked, the other dimension adjusts automatically.
File size is directly tied to resolution: more pixels means more data. The output format also matters. JPEG uses lossy compression, making it ideal for photographs where minor quality loss is invisible. PNG is lossless and supports transparency, perfect for logos and UI graphics. WebP is a modern format that delivers smaller files at equivalent quality to JPEG, and is supported by all major browsers. Choosing the right format and quality level lets you balance visual fidelity against download speed.
Tips & Best Practices
Frequently Asked Questions
What image formats are supported?
The tool supports JPEG, PNG, WebP, and GIF formats for both input and output. JPEG is best for photographs, PNG for graphics with transparency, WebP for modern web optimization, and GIF for simple animations.
Does resizing reduce image quality?
Downscaling (making smaller) generally preserves quality well. Upscaling (making larger) can introduce blurriness since the tool must interpolate new pixels. For best results when enlarging, use increments of 2× or less.
Is my image uploaded to a server?
No. All image processing happens entirely in your browser using the Canvas API. Your images never leave your device, ensuring complete privacy. This also means the tool works offline once the page is loaded.
How do I maintain the aspect ratio?
When the "Lock aspect ratio" option is enabled, changing the width automatically adjusts the height proportionally, and vice versa. This prevents your image from being stretched or distorted.
What is the maximum file size I can upload?
Since all processing happens in your browser, the limit depends on your device's available memory. Most modern devices can handle images up to 50 MB without issues. Very large files (100 MB+) may cause slower processing on mobile devices.
What is the difference between resizing and cropping?
Resizing changes the overall dimensions of the entire image — making it larger or smaller while keeping all content visible. Cropping cuts away portions of the image to focus on a specific area, removing content outside the crop boundary.
What is the best image format for the web?
WebP offers the best balance of quality and file size for most web images. Use JPEG for photographs when broad compatibility is needed, PNG when you require transparency or pixel-perfect graphics, and SVG for icons and logos that need to scale.
How do I resize without losing quality?
Downscaling rarely causes noticeable quality loss. For upscaling, keep enlargements modest (under 2×) and use a lossless format like PNG. If you need a much larger image, consider using AI-powered upscaling tools that can intelligently fill in missing detail.
What image size do I need for printing?
For high-quality prints, aim for 300 DPI (dots per inch). Multiply the desired print size in inches by 300 to get the pixel dimensions. For example, an 8×10 inch print needs a 2400×3000 pixel image. For large-format posters viewed from a distance, 150 DPI is usually sufficient.
Why is my resized image larger than the original?
This can happen when upscaling (increasing dimensions) or when converting to a less efficient format (e.g. JPEG to PNG). It can also occur if the original was heavily compressed. Try lowering the quality slider or choosing a more efficient output format like WebP.