π Image Resizer
Resize by exact pixels or percentage, with aspect-ratio lock.
How to Resize an Image
Upload your image, then either type exact pixel dimensions or pick a percentage scale. The aspect lock keeps proportions correct automatically. Download as PNG, JPG, or WebP. Everything renders from your original file at full quality.
Upload your image. Its original dimensions appear for reference.
Choose Exact pixels for specific dimensions or Percentage for proportional scaling.
Enter width, height, or percent. With aspect lock on, the other dimension follows automatically.
Click Resize and Download and choose your output format.
When to Resize vs. Compress vs. Crop
These three operations solve different problems. Resize changes pixel dimensions: use it when a platform requires 1080 by 1080 or a print needs 2400 by 3000. Compress keeps dimensions but shrinks file size through stronger encoding: use it when the image is already the right size but too heavy. Crop changes composition by discarding edges: use it to reframe or to hit an aspect ratio without distortion. A common workflow combines them: crop for composition, resize to the required dimensions, then export at a quality that balances size and fidelity. Resizing down before compressing is especially effective, because fewer pixels need less data. Avoid resizing up and then compressing hard: upscaling softens, and heavy compression then bakes that softness in with artifacts.
Quality Tips
Always resize from the original, highest-quality file rather than a previously resized copy, because each resampling generation loses a little detail. For downsizing, the browser high-quality smoothing produces clean results with minimal ringing. For upsizing beyond 2x, the dedicated Image Enlarger gives you more control over smoothing. PNG output is lossless and best for graphics, text, and anything you will edit again; JPG at 85 to 92 quality is the sweet spot for photos headed to the web. If a platform recompresses uploads anyway, as social networks do, export slightly larger and higher quality than the minimum to survive their processing gracefully.
Frequently Asked Questions
How do I resize an image to exact dimensions?
Upload your image, enter the target width and height in pixels, and keep aspect lock on if you want proportions preserved (changing one dimension auto-fills the other). Click Resize and Download. The output is rendered from your full-resolution original, not the preview, so quality is maximized.
What does the aspect-ratio lock do?
With the lock on, width and height stay proportional: typing a new width automatically computes the matching height, so circles stay circular and faces are not stretched. Turn it off only when you intentionally want to stretch or squash, for example fitting a fixed banner slot.
Should I resize by pixels or by percentage?
Use exact pixels when a platform or print spec demands specific dimensions, like a 1920 by 1080 hero image or a 300 by 300 avatar. Use percentage when you want a proportional shrink, like halving a batch of photos for email. Both modes respect the aspect lock.
Does resizing reduce quality?
Downsizing is safe and often improves perceived sharpness. Upsizing spreads existing detail over more pixels, so it gets softer the larger you go: for big enlargements use the dedicated Image Enlarger. Saving as PNG is lossless; JPG re-encodes, so keep quality at 85 or above for photos.
What is the difference between resize and crop?
Resizing scales the entire image, keeping all content but changing dimensions. Cropping cuts away outer areas to reframe, keeping pixel density but discarding content. To fit a specific frame, crop first for composition, then resize for exact dimensions. Doing it in that order avoids distorting important subjects.
Are my images uploaded anywhere?
No. Resizing uses the Canvas API locally in your browser. Files never leave your device, nothing is stored, and the tool works offline once the page loads, making it safe for sensitive imagery. There are no file size limits beyond your browser memory, and no queues or waiting rooms.