Image resizer — runs entirely in your browser

What This Tool Does

This tool changes the pixel dimensions of an image — downscale or upscale, single file or batch. Input and output are JPG, PNG, WebP, and AVIF. Resizing runs through the Canvas API directly in your browser; nothing is uploaded, stored, or analysed.

Resizing is not the same thing as upscaling with detail reconstruction. If you stretch an 800-pixel photo to 3200 pixels, the canvas paints plausible transitions between the existing pixels — it does not invent sharpness that wasn’t there. For real detail reconstruction, see image upscaler with an AI super-resolution model.

Pixels or Percent — Which Mode Should I Use?

Pixel input is right when you know the target dimensions: 1920 × 1080 for a hero image, 1080 × 1350 for an Instagram feed post, 800 × 800 for a marketplace thumbnail. Type the width, the height follows from the source aspect ratio.

Percent slider is faster when you want to shrink a batch evenly without thinking about each file. 50 percent halves both dimensions — 4000 × 3000 becomes 2000 × 1500. For email attachments, forum uploads, and CMS prep, that’s often the more direct route.

What Image Sizes Do Social Platforms Want?

The aspect-ratio presets in this tool cover the most common platform specs:

Platform	Use	Pixel size	Ratio
Instagram feed (portrait)	Recommended 2026	1080 × 1350	4:5
Instagram feed (square)	Classic	1080 × 1080	1:1
Instagram Stories / Reels	Vertical full-screen	1080 × 1920	9:16
TikTok / YouTube Shorts	Vertical full-screen	1080 × 1920	9:16
YouTube thumbnail	Standard	1280 × 720	16:9
Pinterest pin	Standard	1000 × 1500	2:3
Facebook / LinkedIn link preview	Standard	1200 × 630	1.91:1
Twitter (X) card	Standard	1200 × 675	16:9

Pick the preset, type the desired width, and the height follows. Platform algorithms still re-crop sometimes, particularly Stories — export slightly larger than spec rather than letting the platform do the resizing for you.

Which Format Should I Pick — JPG, PNG, WebP, or AVIF?

JPG is the standard for photos without transparency. Maximum browser and CMS compatibility, lossy compression with a tunable quality slider. For print-ready files, classic web images, and anything where the recipient might not support newer formats, JPG remains the safe choice.

PNG is lossless and supports alpha transparency. Mandatory for screenshots with crisp text, logos, icons, illustrations, and anything you’ll edit again later — every re-encode cycle is lossless. Files are noticeably larger than JPG for photos.

WebP is a Google-introduced format from 2010 with both lossy and lossless modes, transparency, and very good compression. Typically 25 to 35 percent smaller than JPG at equivalent quality, with around 97 percent global browser reach. The best compromise for web images.

AVIF comes from the AV1 video codec, was introduced in 2019, and trims another 20 to 30 percent off WebP. Supports HDR and 12-bit color depth. Browser reach sits at roughly 95 percent, and encoding is computationally heavier. If your browser can decode but not encode AVIF, this tool falls back to WebP automatically and tells you so in the status line.

What Sets This Tool Apart

A. What every competitor offers:

• Upload one image, type pixel dimensions, download
• Aspect-ratio lock toggle
• JPG and PNG output
• Quality slider for lossy formats
• Drag and drop

B. Where this tool stands out:

• Pure-client by default — no server, no account, no daily cap. The competitor norm is server upload with a free-tier ceiling; only a handful of tools (Squoosh, BIRME, ResizePixel) actually run locally.
• AVIF output with automatic fallback — browsers without an AVIF encoder receive WebP without the user having to check beforehand. Most competitors either don’t offer AVIF at all or surface a cryptic error.
• Aspect-ratio presets for the eight relevant social formats — one click instead of pixel research. Adobe Express has this, most others don’t.
• Bulk mode with ZIP download — multiple images in one run, identical settings, one click for the archive. BIRME can do this, the rest of the market hands you sequential single-file downloads.
• Live target-size preview before resizing — you can see what comes out before clicking Resize.

C. What this tool deliberately does NOT do:

• No cropping or composition editor — resizing and cropping are separate jobs
• No watermark, no border, no filters — minimalist by design
• No AI upscaling with detail reconstruction — see image upscaler
• No HEIC input — see HEIC to JPG for the up-front conversion
• No cloud-side persistence of your settings — privacy-first, every visit starts clean

What Are the Common Issues?

My AVIF download arrives as WebP. Your browser can display AVIF but not encode it. Safari before macOS 13.3 / iOS 16.4, some Android browsers, and certain Chromium forks fall into that bucket. The tool reports this in the status; the WebP result is still 25 to 35 percent smaller than a JPG.

Resizing takes a while. For very large images (kilo-pixel range above 8000) the Canvas API needs a few seconds. The tab stays responsive during the work; AVIF output adds extra time because the AV1 encoder is computationally heavy.

The resized image looks softer than the original. Some softening when downscaling is expected — the browser uses a high-quality bicubic resampler, but every resize loses some sharpness. If the result feels too soft: use the Image Format Converter to re-encode without resizing, or check whether your source has already been scaled twice.

My PNG suddenly lost its transparent background. You picked JPG or AVIF as the output — those formats cannot store transparency, and the tool flattens to white. For transparent backgrounds, choose PNG or WebP.

Is My Image Private — Where Does the Processing Run?

The whole resize pipeline runs in your browser tab via the Canvas API. No upload, no server processing, no tracking. After the first visit, the page works fully offline. For sensitive images (ID scans, medical scans, internal documents), this is the meaningful difference compared to web converters that have to upload your file.

Which Image Tools Are Related?

• Image upscaler — AI-based detail reconstruction up to 4×, also runs locally.
• Image Format Converter — format change without resizing, with WebP and AVIF options plus per-format dedicated tools.
• Background remover — subject extraction without server upload.
• JPG to PDF — bundle multiple images into a single PDF.