Image Resizer

Online Image Resizer

Resize images by exact dimensions, percentage, longest side, or social-media preset. Batch up to 20 images at once — everything runs in your browser.

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Up to 20 images, 30 MB each

Drop images here, or click to browse

Supported: JPG, PNG, WebP, GIF, BMP — up to 20 images at once

Why iKit Image Resizer

Fast, private, browser-only — resize a batch of images and download them in one click.

Four resize modes

Pick exact dimensions, a percentage, a longest-side limit, or a social-media preset.

Batch up to 20 images

Drop a whole folder. Single output downloads directly; multiple come bundled in a ZIP.

Privacy by design

Everything runs in your browser using Canvas. No image is ever uploaded — turn off the network and it still works.

Format conversion

Output as JPEG, PNG, WebP, or keep the original format. Adjustable JPEG / WebP quality.

Social media presets

One click for Instagram square / portrait / story, OG image, X header, YouTube thumbnail, LinkedIn banner, and more.

Aspect-ratio aware

Lock the ratio while typing dimensions, or choose a preset and we letterbox with a background colour you pick.

How the image resizer works

Four resize modes, 16 social presets, all powered by browser-native canvas.

  1. 1

    Choose a resize mode

    Pick exact dimensions (1080 × 1080), a percentage (50%), a longest-side cap (2048 px max edge), or a social-media preset (Instagram square, OG image, YouTube thumbnail, X header, etc.). Each mode handles edge cases differently — letterboxing, aspect-ratio locking, or stretch.

  2. 2

    Decode and resample

    createImageBitmap decodes the source. OffscreenCanvas handles the resampling using bilinear filtering for downscale and bicubic for upscale (browser-implemented). High-quality smoothing is enabled by default to avoid the "crunchy" look of nearest-neighbour shrinking.

  3. 3

    Optional letterbox or background fill

    When the target aspect ratio doesn't match the source, you can either crop, stretch, or letterbox with a chosen background colour. Letterboxing is recommended for social media presets — fills with brand colour, keeps the original framing intact.

  4. 4

    Output JPEG / PNG / WebP

    Choose the output format and quality (for lossy formats). Single image downloads directly; batches of multiple images bundle into a ZIP using the same pure-JS encoder as our image compressor.

Real social-media workflows

One source image, multiple platforms, in 30 seconds.

Cross-posting product shots

Drop one master shot, generate Instagram square (1080 × 1080), OG image (1200 × 630), and X header (1500 × 500) in one batch. Each preset crops or letterboxes correctly so the subject stays visible.

OG image generation for blog posts

Quickly resize a hero image to exactly 1200 × 630 — the size every social platform expects for link previews. Save as WebP for smaller file size with no visible quality loss.

Avatar / profile picture

Resize a square avatar to 400 × 400 (small) or 800 × 800 (large) — exactly the sizes Discord, Slack, and GitHub want. JPEG quality 90 keeps the file under 100 KB.

Bulk down-sizing for email

50 photos at original 12-megapixel resolution → 50 photos at 1920-px longest side, packaged as a single ZIP. The ZIP fits comfortably in any email provider's limit.

Why resize privacy matters

Resizing a personal photo to share online still involves uploading the unmodified original to most resize sites. iKit performs the resize in your browser using OffscreenCanvas, so the original bytes — full resolution, full EXIF — never leave your device. Only the resized output exists, and only on your machine.

  • Original file never uploaded — verifiable in DevTools Network tab.
  • EXIF metadata stripped during re-encoding for added privacy.
  • Single image direct download; multi-image ZIP packaged in-browser.

Frequently Asked Questions

Are my images uploaded anywhere?

No. Resizing happens entirely in your browser using the Canvas API. Your images never leave your device — you can disconnect the network after the page loads and the tool still works.

Which formats are supported?

Input: JPG, PNG, WebP, GIF (first frame only) and BMP. Output: JPG, PNG, WebP, or keep the original. GIF and BMP outputs are converted to PNG.

What's the difference between the four resize modes?

Dimensions = an exact width × height. Percentage = scale by a percent of the original. Longest side = cap the long edge (handy for thumbnails). Preset = pick a known social-media size.

How many images can I process at once?

Up to 20 images per batch, 30 MB each. Single image downloads as a file directly; multiple images are bundled into a single ZIP.

Why does my JPEG look blurry after resize?

Browsers use bilinear sampling. For best results when shrinking dramatically, increase JPEG / WebP quality to 90+. To upscale a small image, no software (browser or otherwise) can recover detail that isn't in the source.