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Resize image online

Resize PNG, JPEG, and photos online in pixels or percent. Scale up or down, stretch when needed, preview output size, download PNG in your browser.

What is image resize?

Image resize changes the pixel width and height of a photo or PNG. Set absolute dimensions in pixels, scale by percent, or stretch width and height independently when proportions are unlocked. This page adjusts pixel count—not DPI metadata or physical inch sizes. Upload an image, choose options, preview output dimensions, and download PNG—all in your browser.

Resize controls

PNG resizer with pixels or percent—change image resolution, stretch when needed, or make a photo larger.

  1. Resize PNG with alpha: Scale PNG uploads while preserving transparency—set width and height in px or percent before export.
  2. Pixels or percent: Absolute px sizing to change resolution, or uniform percent scale—including image size increase above 100%.
  3. Constrain proportions: Lock aspect ratio when resizing by one dimension.
  4. Stretch image online: Turn off constrain in pixel mode to set width and height independently for non-uniform scale.
  5. Live preview and size readout: Compare before and after; output pixel sizes update as you change options—make photos larger up to 8192 px.

How to change image resolution

Steps for online PNG resize, scaling, and stretching.

  1. Upload the image: Drop or click in the input panel (15 MB max).
  2. Pick unit and size: Use pixels for exact dimensions or percent for proportional scale—raise percent above 100% to increase size.
  3. Stretch only if needed: Disable Constrain proportions in pixel mode to stretch width and height differently.
  4. Check output dimensions: Read the resulting width × height under the preview.
  5. Download PNG: Save when the preview matches your goal.

Tips for resizing

Better scaling and stretch results.

  1. Prefer downscaling: Enlarging soft images can look blurry—start from the largest source you have.
  2. Use percent for halves: 50% or 25% is faster than calculating pixel targets manually.
  3. Keep proportions on: Avoid accidental stretch on portraits and product shots.
  4. Stretch with intent: Disable proportions only when you need a deliberate width–height change.
  5. Watch the max edge: Output stops at 8192 px—reduce percent if you hit the limit.
  6. Compare previews: Check the right panel before download for sharpness and framing.

When to resize images

Typical uses for scaling photos and PNGs.

  1. PNG and JPEG exports: Hit exact pixel widths for icons, banners, or storefront assets.
  2. Smaller file size: Shrink large photos before email or upload with percent downscale.
  3. Social dimensions: Scale toward platform width and height guidelines in pixel mode.
  4. Square or custom ratios: Turn off proportions to reshape toward a square or non-uniform target.
  5. Print pixel prep: Set pixel dimensions before handing off to layout or print tools.
  6. Quick one-off scale: Resize a single file in the browser without opening desktop apps.

Why use this resize tool

Benefits of browser-based scaling.

  1. Px and percent: Match common PNG resizer and stretch workflows in one page.
  2. Private: Images stay on your device—no server upload.
  3. Dimension readout: See original and output pixel sizes on screen.
  4. Smooth scaling: High-quality Canvas interpolation for upscaling and downscaling.
  5. Optional stretch: Unlock proportions when you need non-uniform width and height.
  6. Free: Unlimited previews and downloads.

Technical details

How resize processing works here.

  1. Canvas drawImage: Source bitmap scaled to target width and height with smoothing enabled.
  2. Percent mode: Both dimensions multiplied by new value ÷ 100.
  3. Constrained pixels: Secondary dimension derived from aspect ratio of the upload.
  4. Independent pixels: Separate width and height when proportions are off—enables stretch.
  5. Alpha channel: Preserved through scale and PNG export.
  6. Input limits: 15 MB upload; 8192 px max input and output edge.

Frequently Asked Questions

Have questions? We have answers.

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