Image Size Analyzer
See exactly what is inside an image file: bytes, pixel dimensions, aspect ratio, megapixels, transparency and bytes per pixel — measured locally, with nothing uploaded.
Inspected read-only in your browser, not uploaded. Your original file is never modified.
No display width given, so dimension recommendations are estimates based on a typical 1920 px layout.
Your image is measured read-only in your browser on your own device and is never uploaded to a server. The readings come from pixels decoded into this tab, and that data is cleared on close or refresh.
How to measure file size, pixel density and decoded memory
- Choose one image from your device. The analyzer supports JPG, PNG, WebP, GIF, BMP, TIFF and SVG, subject to successful decoding.
- Compare the exact byte count alongside Decimal size (1 KB = 1,000 bytes) and Binary size (1 KiB = 1,024 bytes).
- Inspect Pixel grid & density (bytes per pixel) and Decoded RGBA memory to see how much browser RAM the uncompressed bitmap occupies.
- Use the Portal & upload limit check to test whether the file passes a specific KB cap under both 1,000-byte decimal KB and 1,024-byte binary KiB rules.
- Copy the report for documentation or use the linked compressor and resizer tools if you need to modify the file.
How to download the result
The analyzer is a read-only inspection tool and does not modify or re-encode your image. Copy report copies the full technical breakdown (bytes, decimal KB, binary KiB, dimensions, BPP, and RGBA memory) to your clipboard, and Download original saves your unchanged source file.
File handling and usage data
Measurements are derived from the selected file in local browser memory, with temporary preview URLs rather than a server upload. Reloading removes the report and selection, while any files you have saved remain in your Downloads folder. Usage analytics may include image format and approximate megapixels; image pixels and the source filename are not included.
Full details are in the Privacy Policy.
Troubleshooting
Why do the measurements differ from the file manager?
Some file managers label binary units (1,024 bytes) as KB or MB, whereas web tools often use decimal units (1,000 bytes). This analyzer displays both decimal KB and binary KiB side by side so you can compare the exact underlying byte count.
Why does a PNG report no transparency?
The extension permits transparency but does not prove that the image uses it. The analyzer samples decoded alpha values; a completely filled background is opaque.
Why is a small file too large to analyze on my phone?
Compressed bytes must be expanded into an uncompressed RGBA bitmap in memory (width × height × 4 bytes). Very large dimensions can exceed device RAM even when the stored file is small.
Measure an image before you change anything
This analyzer reports the numbers behind a file: bytes, pixel dimensions, aspect ratio, megapixels, detected format and MIME type, transparency, and bytes per pixel. These are measurements, not opinions, and they are all read in your browser.
It is the quickest way to answer questions like "why is this 6 MB?" or "is this PNG actually transparent?" without opening a desktop editor.
Bytes, pixels and the relationship between them
File size on its own says very little. A 900 KB file is heavy for a 600 px thumbnail and remarkably light for a 4000 px photograph. Dividing bytes by pixels normalises that, which is why the analyzer shows both raw values and the derived density.
Megapixels matter separately, because decoded images occupy roughly width × height × 4 bytes of memory regardless of how small the compressed file is. That is what makes very large images slow to decode on phones even when they download quickly.
Typical bytes-per-pixel ranges across formats
Comparing your file's measured bytes-per-pixel (BPP) reading against standard benchmarks immediately tells you whether the file is bloated by encoding settings or by raw dimensions:
- 0.08–0.25 BPP: typical well-tuned WebP or JPEG web photograph at quality 75–82.
- 0.30–0.65 BPP: high-quality camera JPEG (quality 90–95) or detailed UI graphic with alpha.
- 0.80–2.50+ BPP: uncompressed or lossless PNG photograph, BMP, or TIFF scan where lossless storage is keeping invisible sensor noise.
What to do with the numbers
High bytes per pixel with no transparency points at the wrong format or a too-lossless encode. Large dimensions relative to your layout point at resizing. A large total with reasonable density on both counts usually just means the image is genuinely big and should be resized before compressing.
Decimal vs binary file-size units
Online upload portals and operating systems sometimes disagree on whether 1 KB means 1,000 bytes (decimal, SI standard) or 1,024 bytes (binary, KiB). This analyzer reports decimal kilobytes alongside the exact raw byte count so you can verify strict form ceilings without getting caught by a 2.4% unit discrepancy.
If the measured dimensions exceed the receiving form's requirement, correct them with Resize Image.
Frequently asked questions
What is bytes per pixel and why does it matter?
It is the file size divided by the pixel count, and it is the cleanest way to compare compression across images of different dimensions. A well-compressed web photograph usually lands around 0.1 to 0.3 bytes per pixel; a lossless PNG photograph can be several times that.
How is transparency detected?
The decoded image is drawn to a small off-screen canvas and its alpha channel is sampled. A PNG that happens to be fully opaque is reported as having no transparency, because that is what the pixels say.
Does the analyzer read EXIF or location data?
No. It reads the file's size, MIME type, extension and decoded pixel data only. It never reads or transmits camera or location metadata.
Why does a 2 MB JPEG use 48 MB of browser memory?
Compression only applies to the stored file on disk. To display or edit an image, the browser must decode every pixel into 4-byte RGBA values (Red, Green, Blue, Alpha). A 4000×3000 (12 MP) photo therefore occupies 12,000,000 × 4 = 48 MB of uncompressed RAM per canvas buffer.
How is the aspect ratio simplified in the report?
The analyzer divides the decoded pixel width and height by their greatest common divisor (GCD) to show the exact integer ratio (such as 16:9, 4:3 or 1:1), alongside the raw pixel dimensions.
When not to use this
The analyzer only reports measurements; it does not change your file. Move to a resizer or compressor once you know what is wrong.
Physical print size depends on a DPI value the destination chooses, so do not treat the stored DPI tag as proof of print dimensions.