Auto-enhance your photos

Flat, hazy or underexposed photos usually need the same small correction. This measures what each image actually needs and applies it — and leaves alone the ones that are already fine.

What it corrects

Most disappointing photos share one problem: the tones are bunched into a narrow band instead of spanning the full range from black to white. Shot through a window, on an overcast day, or into haze, and everything comes out grey and lifeless.

The fix is auto-levels. The image's histogram is measured, the points where the darkest and brightest real detail sit are found, and the tones between them are stretched to fill the full range. Blacks become black again, highlights recover, and the picture gains depth without anything being invented.

A gentle exposure correction follows if the image is consistently too dark or too bright, along with a slight lift in colour intensity.

Restraint is the point

An auto-enhance that visibly mangles a photo which was already fine is worse than one that does nothing, because you cannot tell in advance which you are going to get.

So every adjustment here is measured against the image's own statistics, and skipped when the image does not need it. A correctly exposed photo comes back very close to how it went in, and the tool says so rather than claiming an improvement it did not make.

The exposure adjustment is also clamped. Aggressive correction is exactly what makes automatic enhancement look like a filter, and a filter is not what you asked for.

Colour balance is deliberately left alone. Stretching each colour channel independently is a white-balance correction, and applying one uninvited turns a warm sunset into a grey afternoon. The channels are stretched together, so the mood of the photo survives.

What it will not fix

Worth being straight about the limits. Blur from a shaky hand or a missed focus cannot be corrected — the detail was never recorded. Heavy noise from a dark room is not removed, and lifting the exposure can make it more visible.

Areas that are completely blown to white or crushed to black hold no detail to recover. This works on tone and contrast, which is what most ordinary photos actually need, and it will not rescue a fundamentally broken shot.

Nothing is uploaded

The correction runs on your device. Your photo is decoded in the browser tab, adjusted in memory, and handed back as a download — it is never sent anywhere.

That is unusual for photo enhancement, which is normally the sort of thing a server does. Load the page, disconnect from the internet, and enhance a photo anyway to confirm it.

Quick questions