What is actually wrong with most photos
The same three faults account for most disappointing photos: a colour cast from indoor lighting that turns whites yellow, flat contrast from haze or backlight, and the mild softness every phone sensor produces. None of them is damage — the information is there, presented badly.
Auto enhancement here is those three corrections with sensible strengths: a grey-world white balance to neutralise the cast, a percentile-clipped contrast stretch to use the full tonal range, and a restrained sharpening pass. Saturation gets a nudge, not a shove.
Because each correction is a slider, auto is a starting point rather than a verdict. Food photos often want more colour, portraits want less sharpening, and a deliberately moody shot wants the contrast pulled back — you decide, watching the preview.
Why deterministic beats AI here
AI photo enhancers re-synthesise the image — that is how they smooth skin and rebuild detail. The cost is fidelity: they have been caught changing faces, inventing texture, and rewriting the fine print in photographed documents. The photo stops being a record of anything.
Arithmetic has no such ambitions. A contrast stretch maps existing tones onto a wider range; white balance scales three channels; sharpening amplifies edges that exist. Run it twice, get the identical file — and nothing appears that the camera did not capture.
That property matters best exactly where enhancement is most needed: marketplace product photos, insurance documentation, listing photos of a flat. Buyers and assessors are entitled to a truthful picture, and this tool is incapable of an untruthful one.
Using the sliders like a retoucher
Work in the sliders' order. Fix white balance first — every judgement about colour is wrong while the cast is there. Then contrast, which sets the tonal foundation; then saturation, which reads differently once contrast is right; sharpening always last.
The hold-to-compare button is the discipline. Eyes adapt within seconds to whatever is on screen, and edits creep stronger and stronger while still looking normal. Flicking back to the original resets your reference — if the enhanced version jolts, you have gone too far.
The preview works at a reduced size for speed, and your download is re-processed at full resolution with the same settings — so what you approved is what you get, just with all the pixels.