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.
Your image is processed locally in your browser. It is never uploaded to our servers. No fixed size limit — we adapt to what your device can handle. Very large files may take longer or show a warning.
No display width given, so dimension recommendations are estimates based on a typical 1920 px layout.
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.
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.
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.