How is the aspect ratio simplified?

We compute the greatest common divisor of width and height. A 1920x1080 image shows as 16:9.

Why does MIME differ from the file extension?

The MIME is sniffed from the file's magic bytes, which is what browsers and servers actually trust. Mismatched extensions are common.

inspect · dimensions · aspect · local

Inspect image dimensions and metadata

Get width, height, aspect ratio, megapixels, file size, MIME type, and bytes-per-pixel for any image. Runs locally.

Image Dimension Inspector

Dimensions

—

Size

—

MIME

—

Bytes/px

—

input · image

image/* · runs locally · nothing uploaded

output · preview

Details appear here

Quick Start

How it works

Pick an image, tune the options, then download the result. Everything runs in your browser.

01
Pick any image
PNG, JPEG, WebP, GIF, BMP, AVIF, SVG — anything the browser can decode.
Files stay in memory as an HTMLImageElement — the original bytes are never uploaded, and EXIF metadata is preserved until you explicitly transform it.
inputuploadcanvaslocaldecode
input · bytesimage · loaded
```
load: image/*
```
loaded · decodedcanvas · ready
02
Sniff format
Magic-byte check identifies the MIME type, independent of the file extension.
Encoder quality is exposed where the format supports it — JPEG and WebP get a 0–1 quality slider; PNG is lossless. Options re-render the canvas immediately.
mimeoptionslive previewencoderquality
mime · tunable— · live
```
sniff(header)
```
options applied · liveencoder · live
03
Read pixel size
Decode the image to read naturalWidth/naturalHeight and derive aspect ratio + megapixels.
Pixel work runs on the Canvas 2D context — drawImage resamples with the browser’s bilinear filter and getImageData/putImageData back per-pixel passes.
dimsrenderCanvas 2Dpreviewpx-perfect
dims · resampled— · px-perfect
```
width × height
```
preview · livepx-perfect
04
Copy or move on
One click copies the full detail set to your clipboard.
Downloads ship via a hidden anchor with an object URL — no server round-trip, and the file on disk is untouched. The output filename inherits a sensible suffix.
copydownloadblobclient-sideobject URL
ok · blobready · saved
```
clipboard ← rows
```
shipped · ready to shipsuccess

Pro tips

Browser-only image work that scales

Convert with quality control

JPEG/WebP let you pick a 0–1 quality. Default 0.92 is a good compromise of size and visible quality.

PNG isn’t free

Use PNG only for transparency or sharp edges. For photos, WebP is smaller at the same perceived quality.

Strip EXIF for privacy

Photo EXIF often contains GPS, camera model, and timestamps. Strip before sharing public uploads.

Watch the colour profile

Convert to sRGB before web export. Wide-gamut images render oversaturated in non-managed browsers.

AVIF when it’s available

AVIF beats WebP on size at the same quality. Detect support via <picture> with fallbacks.

Lazy-load below the fold

Add loading="lazy" on <img>. The browser handles scheduling — no IntersectionObserver needed.

Use Cases

When to use this tool

Common workflows it speeds up.

Asset audits

List dimensions across many assets for cleanup. Decoded into a Canvas 2D context — original bytes never leave the tab, so you can process customer-uploaded photos, internal screenshots, or sensitive diagrams without privacy concerns.

px-perfect

OG image checks

Verify 1200x630 / 1.91:1 for socials. Encoders expose quality 0–1 where the format supports it (JPEG, WebP); PNG and AVIF stay perceptually lossless. Pick 0.85 for web, 0.95 for archival, 0.7 for thumbnails.

quality-tunable

Avatar uploads

Reject under-sized profile photos client-side. Pair with the EXIF Stripper before sharing user-uploaded photos publicly. Camera serial numbers, GPS coordinates, and timestamps often hide in image metadata and leak more than the picture itself.

format-aware

Print prep

Check megapixels before sending to print. Output preserves colour profile (sRGB) so it renders consistently across browsers, monitors, and print pipelines. Wide-gamut workflows can opt into Display P3 for modern Apple devices.

EXIF-safe

Storage debugging

Spot oversized images bloating your bucket. Re-runs only on option changes, never on window resize, so the canvas stays responsive on large images. drawImage uses the browser's bilinear filter for fast resampling.

client-side

Browser support

Confirm the real MIME when extensions lie. Downloads as .png, .jpg, .webp, or .avif with the correct MIME so editors apply native handling on save. The filename inherits a sensible suffix derived from the input.

compression-ready

FAQ

Frequently asked questions

Why does the MIME sometimes differ from the extension?

Magic-byte sniffing reads the file header. If someone renamed a JPEG to .png, sniffing finds the truth.

Where does aspect ratio come from?

GCD of width and height — so 1920x1080 reports 16:9, not 240:135.

Is megapixels just width × height?

Yes, divided by 1,000,000 and rounded to 2 decimals.

Does it work for SVG?

SVG decoding uses CSS pixels; vector files often report intrinsic size or a viewBox default.

Is anything uploaded?

No. Everything runs locally in your browser.

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