Event Photo Quality Checker

Four things. Sharpness, meaning how much each pixel stands out from its neighbours: lots of crisp edges give a high score. Exposure, from the average brightness on a scale of 0 to 255 and from the share of pixels that are pure black or pure white, where no detail is left. Noise, meaning how much pixels vary in the most uniform areas of the image, where any leftover variation is almost always grain. Resolution, from the pixels of the original file, with the print size it allows at 300 dots per inch. The summary counts how many of the four measurements fall within the thresholds: there is no overall score, because adding up different quantities into a single grade would mean making it up.

No. All the calculation happens in the browser, on your device: the photo never leaves it, is not stored and does not pass through us. You do not need to sign up, and no trace of the image remains after you close the page. That is why files are limited to 25 MB: beyond that, processing would put too much strain on your phone or computer.

Because the sharpness measurement detects detail, not focus. A white wall, a clear sky or a plain backdrop are in focus but have little detail, so they show up as "low detail" even when the shot is perfect. The reverse is also true: a very grainy photo can come out as rich in detail precisely because of the grain, since sharpness and noise are not independent measurements. And a deliberately dark or blurred photo can be excellent yet show up here as "worth checking". The thresholds are stated conventions, not photographic rules: read the result as a pointer, not a verdict.

It is probably in HEIC format, the iPhone default, which several browsers cannot open. On your phone, share the photo and choose "JPEG" when sending it, or export it as JPG or PNG and try again. JPG, PNG, WebP and AVIF work without any problems.