// inspect format, dimensions, and details in one click
Instantly inspect image format, dimensions, aspect ratio, color mode, and file details — browser-based, free, no upload required.
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JPEG · PNG · WebP · GIF · BMP · SVG · AVIF · ICO
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Drop or select an image to see its full detailsDrag an image onto the drop zone, click to browse, or paste a remote image URL.
Click "Inspect Image" to read format, dimensions, aspect ratio, file size, and more.
Click "Copy Report" to copy all details to your clipboard for documentation or sharing.
Image Format Inspector reads the intrinsic properties of any image file directly in your browser — no server upload, no account. It identifies the format, pixel dimensions, aspect ratio, approximate file size, megapixel count, and whether transparency is present.
Everything is processed locally using the browser's native Canvas and File APIs, so your images stay private.
No. All processing happens entirely in your browser using the File API and HTML Canvas. Your image never leaves your device. This makes it completely private and works offline once the page is loaded.
The inspector supports all formats your browser can natively render: JPEG, PNG, WebP, GIF, BMP, ICO, SVG, and AVIF. Browser support for AVIF and some obscure formats may vary slightly.
The aspect ratio is computed by finding the greatest common divisor (GCD) of the width and height, then simplifying. For example, a 1920×1080 image becomes 16:9. Common named ratios like 4:3, 1:1, and 21:9 are also labeled when applicable.
Yes. Paste a direct image URL into the URL field and click "Load". Note that some servers block cross-origin requests (CORS), which may prevent the URL from loading. In that case, download the image and use the file drop instead.
Transparency (alpha channel) means the image can have see-through or semi-transparent pixels. PNG and WebP support transparency; JPEG does not. This is important when placing images on colored backgrounds or in designs where the background should show through.
Megapixels = (width × height) ÷ 1,000,000. A 1920×1080 image is 1920 × 1080 = 2,073,600 pixels, or approximately 2.07 megapixels. This metric is commonly used to describe camera resolution and image quality.
Browsers decode all images into RGB (or RGBA with alpha) for rendering, regardless of their original color space. CMYK images, for instance, are converted to RGB by the browser's image decoder. For CMYK detection, a server-side tool with raw binary parsing would be required.
When you select a local file, the size is read directly from the file system — it is exact. When loading from a URL, size is estimated from the image's data representation in the browser, which may differ slightly from the actual on-disk file.
An image format inspector is a tool that reads the intrinsic metadata and pixel properties of an image file without requiring any external service or server upload. It tells you what format an image is encoded in, how large its canvas is in pixels, what aspect ratio it occupies, and a variety of technical attributes that affect how the image behaves in browsers, design tools, and publishing platforms.
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Different image formats serve radically different purposes. Using the wrong format in the wrong context can bloat your page size, break transparent overlays, cause rendering inconsistencies, or fail accessibility requirements. Here is a quick breakdown of the most common formats and their intended use:
Image dimensions are expressed in pixels: width × height. A 1920×1080 image has 1,920 pixels horizontally and 1,080 pixels vertically. This is independent of how large it appears on screen, which depends on CSS sizing, display DPI, and the device's pixel ratio.
High-DPI (Retina) displays use a device pixel ratio of 2× or even 3×, meaning you need a 2× or 3× larger image to appear crisp. For example, a 200×200 CSS pixel element on a 2× Retina display requires a 400×400 source image to look sharp.
Megapixels — the total number of pixels divided by one million — give you a sense of the image's raw data density. A 12-megapixel image from a modern smartphone is 4032×3024 pixels. For web use, anything above 2 megapixels is typically overkill unless you are providing a zoomable image or high-resolution print asset.
Aspect ratio is the proportional relationship between an image's width and height, expressed as a ratio like 16:9, 4:3, or 1:1. It is one of the most important properties to get right in web and app design because it governs how images fit into layouts, responsive containers, and social media cards.
Common aspect ratios and their contexts:
Mismatched aspect ratios cause images to be cropped, letterboxed, or distorted — all of which degrade the user experience and can break carefully designed layouts.
The alpha channel is a fourth channel in an image's color data — alongside Red, Green, and Blue — that stores transparency information. Pixels with a full alpha value are completely opaque; pixels with zero alpha are completely transparent; values in between create semi-transparency.
Not all formats support alpha. JPEG, BMP, and standard GIF do not carry a proper alpha channel. PNG, WebP, AVIF, and some GIF variants do. When you place an image with transparency on a colored background in a web page or design tool, the background shows through the transparent regions. Without alpha support, a transparent area appears as a solid color — usually white or black — which can ruin a design.
Use this inspector to confirm whether your image has transparency before assuming it will composite correctly in your project.
This tool uses two core browser APIs to extract image information without any server involvement. First, the File API reads the selected file's metadata — name, MIME type, and size — directly from the operating system. Second, the HTML Canvas API renders the image into an off-screen canvas, allowing the tool to read back pixel dimensions and detect color properties like the presence of an alpha channel.
The MIME type reported by the browser (e.g., image/jpeg, image/png, image/webp) is used to determine the format label. For URL-loaded images, the Content-Type response header provides the same information. Format labels are derived from this MIME type, not from the file extension, making detection reliable even when extensions are missing or incorrect.
Because all processing is local, this tool works instantly regardless of internet speed (after the page loads), handles images of any size up to browser memory limits, and never transmits your files to any external server.
Once you know your image's format and dimensions, here are actionable next steps for common scenarios:
Google's Core Web Vitals framework — which directly influences search ranking — includes metrics that are heavily impacted by image format and size. Largest Contentful Paint (LCP) measures how quickly the largest visible content element loads, and it is almost always an image. Oversized or inefficiently formatted images are the number one cause of poor LCP scores.
Cumulative Layout Shift (CLS) is another metric affected by images: when images load without predefined dimensions, they push other content around the page as they appear, creating a jarring visual shift. By inspecting your image dimensions ahead of time, you can set correct width and height attributes in your HTML, which allows the browser to reserve the correct space before the image loads — eliminating layout shift entirely.
Using this tool as part of your pre-publish workflow helps you catch format and dimension issues early, before they cost you page speed score points.