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Image Transparency Checker

Verify whether an image is truly transparent, inspect partial-alpha edges on multiple backgrounds, probe exact RGBA pixels, review alpha distribution and export a browser-local audit without uploading the file.

exact browser-local alpha inspection

Image Transparency Checker — inspect the pixels, not the filename

Drop, choose or paste an image. Verify decoded alpha pixel-by-pixel, switch preview backgrounds to reveal halos, inspect an alpha map and histogram, and click any point for its exact RGBA/alpha value.

local · exact ≤24MP · no upload

Drop, choose, or paste an image

PNG, WebP, AVIF, GIF, JPEG and other browser-decodable formats. JPEG is expected to decode fully opaque.

Nothing is uploaded. Exact counting stops rather than pretending a downsample is exact above 24 million pixels.

—Transparency class

—Dimensions

—Exact decoded pixels

—Fully transparent

—Semi-transparent

—Opaque

—Average opacity

—Minimum alpha

—Semi pixels touching clear

—Outer-border alpha

Choose an imageA PNG filename does not prove transparency. This tool reads the decoded alpha values.

Image pixels stay in this tab unless you explicitly export a report or alpha map.

Truth boundary: decoded pixel alpha is the primary evidence. A container can support or advertise alpha while every decoded pixel is still opaque. GIF/animated formats may expose only the browser-decoded frame to Canvas. Checkerboards and colored backgrounds are previews — they are never baked into your source file by this read-only checker.

Core image workflows

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How to verify transparency before publishing an asset

Check more than the filename

PNG, WebP and AVIF can carry alpha, but a particular file may still be fully opaque. The decoded counts tell you whether any pixel actually uses alpha below 255.

Inspect edges on white, black and magenta

Soft antialiasing, shadows and leftover matte color can disappear on one background and become obvious on another. Semi-transparent highlight helps locate the pixels that create that fringe.

Use the alpha histogram for shape, not quality scoring

A logo can legitimately have many fully transparent pixels, while a soft shadow can legitimately use many partial values. The histogram describes opacity distribution; it does not decide whether the art is good.

Probe suspicious pixels directly

Zoom in and click an edge to read the browser-decoded RGBA value. Alpha 0 is fully clear, 255 fully opaque, and 1–254 partially transparent.

Container evidence and pixel evidence answer different questions

A PNG color type or WebP alpha flag says the format can carry transparency. Pixel evidence tells you whether the decoded image actually uses it. This page reports both instead of treating them as identical.

Recheck the final delivered file

Image editors, converters and publishing systems can flatten alpha or change edge colors. If transparency matters in production, inspect the final exported/delivered asset rather than only the source working file.

Browser-local limits

Canvas-based export is browser dependent. PNG is broadly available; JPEG/WebP quality and support can vary, and metadata may not be preserved through canvas re-encoding.

Transparency is an alpha-channel property

An image can contain an alpha channel even when every pixel is fully opaque, and a visually solid background can hide partially transparent edges. Conversely, formats such as ordinary JPEG do not encode per-pixel alpha. The useful question is whether decoded pixels actually contain alpha values below full opacity.

Check the intended compositing result

Inspect transparent images over more than one background, especially around antialiased edges, shadows, and logos. Color profiles, premultiplied-alpha handling, export settings, and conversion to a format without alpha can change appearance. If transparency matters for production, verify the final exported file—not only the source preview—and make sure the destination format and application preserve the alpha channel.

Practical guide and verification

Use the tool first, then use these checks to interpret, verify and hand off the result without displacing the primary workflow.

Distinguish an alpha channel from visible transparency

A file can technically include alpha while every pixel is fully opaque, and a white background can look transparent when viewed on white. Use the pixel counts and checkerboard preview together. The question is both whether alpha information exists and whether any pixel actually uses it.

Inspect semi-transparent edges on contrasting backgrounds

Anti-aliased cutouts often contain a fringe of partially transparent pixels. Preview the image over light and dark backgrounds when the destination may vary. A halo that is invisible on the checkerboard can become obvious after compositing, especially around hair, logos, shadows or exported text.

Remember that the decoded browser image is the evidence

The checker reports pixels after the browser decodes the selected file. It does not certify every metadata chunk, color-management behavior, animation frame or downstream encoder. If a production pipeline rewrites the image, run the final delivered file through the checker again rather than assuming transparency survived.

Use counts to diagnose, not to judge image quality

A high transparent percentage may be correct for a small logo on a large canvas, while zero transparency may be correct for a photograph. Interpret fully transparent, semi-transparent and opaque counts in relation to the intended asset. The numeric result alone does not determine whether the image is well prepared.