UFOZoo

Image Resizer — Resize, Rotate, and Flip Images Online

Resize images online — Fit/Fill/Stretch scaling modes. Rotate, flip, set dimensions in pixels or percent. Output JPEG/PNG/WebP with quality. 100% browser-based.

Features

  • ✓Resize images to exact dimensions — by pixels or percentage
  • ✓Fit, Fill, and Stretch resize modes for different scaling needs
  • ✓Rotate 90° clockwise, counter-clockwise, or 180°
  • ✓Flip horizontally or vertically
  • ✓Maintain aspect ratio option — keep proportions when changing size
  • ✓Pixel input with slider (1-500%) for quick scaling
  • ✓Output as JPEG, PNG, or WebP — defaults to original format
  • ✓Adjustable quality for JPEG and WebP output (10-100%)
  • ✓Real-time preview — see the result instantly as you adjust
  • ✓Paste from clipboard (Ctrl+V) for instant editing
  • ✓All processing happens in your browser — no server uploads
  • ✓100% free with no file size limits or watermarks

How to Use

  1. 1Open an image by clicking the drop area, dragging a file onto it, or pasting from clipboard (Ctrl+V).
  2. 2Choose a resize mode: Fit (scale to fit), Fill (fill and crop), or Stretch (exact dimensions).
  3. 3Set target dimensions — switch between Pixels for exact size or Percentage for proportional scaling.
  4. 4Toggle Keep Aspect Ratio on or off. When on, changing width or height automatically adjusts the other.
  5. 5Apply rotation (90° clockwise, counter-clockwise, 180°) or flip (horizontal, vertical) if needed.
  6. 6Select output format and adjust quality for JPEG/WebP, then click Save to save the result.
  7. 7How to resize an image to 1920×1080 for a desktop wallpaper: open your image, select Pixels mode, enter 1920 for width and 1080 for height. Choose the Fill resize mode to crop and fill the screen completely, or Fit to keep the entire image visible with letterboxing.
  8. 8How to resize a product photo to a standard e-commerce size: open the product image, set width to 800 pixels and enable Keep Aspect Ratio so height adjusts automatically. Select the Fit mode to ensure the entire product is visible, then save as JPEG with 85% quality.

Frequently Asked Questions

What's the difference between pixels and percentage?

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Pixels: set exact target width and height (e.g. 800×600). The output will be those exact pixel dimensions. Percentage: scale relative to original (e.g. 50% = half the width and height, 200% = double). Both modes support maintaining aspect ratio.

What's the difference between Fit, Fill, and Stretch?

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Fit: scales proportionally so the entire image fits within your target dimensions — no cropping, no distortion, but may leave empty space. Fill: scales proportionally to fill the target area completely — may crop edges. Stretch: forces the image to match exact width and height — may distort if the aspect ratio differs.

Does resizing reduce image quality?

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Downscaling (making smaller) usually keeps the image sharp. Upscaling (making larger) may cause pixelation since the browser must generate new pixels. For JPEG/WebP output, you can adjust quality from 10-100%. We recommend 80-90% for a good balance of size and quality.

Is there a maximum image size I can resize?

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The practical limit depends on your device's available memory. Images up to 50MB typically work fine. Very large images (100MB+) may cause performance issues on lower-end devices. The max dimension is capped at 16384 pixels to prevent browser crashes.

What image formats are supported?

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The tool accepts JPG/JPEG, PNG, WebP, AVIF, BMP, GIF, and SVG as input — any format the browser can render. Output can be saved as JPEG, PNG, or WebP. SVG input will be rasterized (converted to pixels) during resizing.

Does rotation or flip affect image quality?

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Rotating by 90°, 180°, or 270° and horizontal/vertical flips are lossless operations — they just rearrange the pixel data without re-encoding. No quality loss occurs from rotation or flip alone.

Is my image uploaded to a server?

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No. All processing happens entirely in your browser using the HTML5 Canvas API. Your image is never uploaded, stored, or transmitted anywhere. You can even use this tool offline after the page loads.

Are there any watermarks or usage limits?

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No watermarks, no registration, no file size limits, and no hidden charges. This tool is completely free to use for any purpose — personal, commercial, or educational.

Can I resize multiple images at once?

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No, this tool processes one image at a time. For batch resizing, each image needs to be processed individually since dimensions and aspect ratios vary. The real-time preview helps you verify the result before saving.

What happens when I upscale an image beyond its original size?

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Upscaling (enlarging) an image causes the browser to generate new pixels through interpolation. The result may appear soft or pixelated, especially at high scaling percentages. For the best quality, avoid upscaling beyond 200% of the original dimensions.

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