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About this tool
Analyze image quality with nine professional metrics including sharpness, brightness, contrast, noise, exposure, and histogram analysis.
Image Quality Checker scores a photo on nine measured metrics — sharpness, brightness, contrast, noise, exposure, white balance, saturation, dynamic range and resolution — and combines them into one 0-100 score with a letter grade, weighting sharpness at 20%, noise and resolution at 15% each, brightness, contrast, exposure and white balance at 10% each, and saturation and dynamic range at 5% each. Every measurement runs on the image's real pixels through a canvas, using the standard 0.299R + 0.587G + 0.114B luma formula, alongside a luminance and per-channel RGB histogram. It ends with concrete suggestions such as which axis is dragging the score down, and a downloadable text report.
Open Image Quality Checker on AltFTool — it loads instantly in your browser.
Drop a JPG, PNG, WEBP or HEIC image up to 20MB on the uploader, or paste one from the clipboard.
The checker reads the canvas pixels and returns an overall score out of 100 with its grade — A+ at 90, A at 80, B+ at 70 — alongside Image Info and the Quality Metrics bars.
Open Histogram Analysis for the luminosity and RGB plots, then press Download Report for image-quality-report.txt.
Sharpness carries 20% and resolution and noise 15% each, so a soft or tiny image cannot be rescued by good saturation.
Low scores map to named suggestions — blurry, too dark, overexposed, flat contrast, noisy, colour cast, low resolution — instead of a single verdict.
Luminance and separate R, G and B histograms let you confirm a clipping or cast diagnosis rather than take the score on faith.
The grade bands are A+ at 90 and above, A at 80, B+ at 70, B at 60, C+ at 50, C at 40 and D below that. Anything at 70 or above is treated as good in the readout, and the score gauge turns amber below 70 and red below 40.
It walks every pixel and sums the absolute luminance difference against its right-hand and lower neighbours, giving an average gradient magnitude that is then scaled to 0-100. Crisp edges produce large neighbour-to-neighbour differences, blurred ones produce small ones, and a sharpness score under 40 is called out as blurry.
It counts pixels with luminance below 25 as underexposed and above 230 as overexposed, and starts deducting once either group passes 5% of the image. Above 20% in either direction the tool explicitly warns about significant shadow or highlight clipping.
The resolution score is stepped by total pixel count: under 0.1 MP scores 20, under 0.3 MP scores 40, under 0.6 MP scores 60, under 1 MP scores 80, and 1 MP or more scores 100. Since resolution is 15% of the total, a small crop or a downscaled web copy will cap the overall grade no matter how good it looks.