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About this tool
Compare image resolution, quality, sharpness, DPI, and compression like a professional. Analyze two images side-by-side with detailed metrics.
Image Resolution Compare puts two images side by side and scores each on eight measured axes — resolution, sharpness, compression, noise, colour, brightness, contrast and dynamic range — weighting resolution and sharpness at 20% apiece and the other six at 10% each to produce a 0-100 quality score. It also reports pixel dimensions, megapixels, aspect ratio, orientation, file size and a compression ratio of uncompressed bytes to actual bytes, and checks both images against 12 social platform size presets. Results export as PDF, CSV or JSON so a comparison can be attached to a brief or a ticket.
Open Image Resolution Compare on AltFTool — it loads instantly in your browser.
Drop a file into the Image A zone and a second into Image B — the zones accept SVG, PNG, JPG and GIF.
Read the side-by-side comparison and the 0-100 quality score, which weights resolution and sharpness at 20% each and the other six metrics at 10%.
Check which of the 12 social presets each image fits, then use Export PDF, Export CSV, Export JSON or Export PNG Preview.
Both files run through the same downscaled sampling and the same eight-metric scoring, so the comparison is like for like rather than eyeballed.
Resolution and sharpness are scored independently, which is how a bigger file that is soft can come out behind a smaller one that is crisp.
Instagram post and story, Facebook post and cover, LinkedIn banner and post, YouTube thumbnail, Pinterest pin, X post, TikTok cover and WhatsApp status.
As a weighted sum: resolution 20%, sharpness 20%, and compression, noise, colour, brightness, contrast and dynamic range 10% each. Resolution is banded by megapixels — 12 MP or more scores 100, 8 MP scores 80, 4 MP scores 60, 2 MP scores 40 and anything below that scores 20.
It divides the uncompressed size (width x height x 3 bytes) by the actual file size, so a ratio of 10 means the file is a tenth of its raw pixel data. Ratios above 10 score well for efficiency, but above 20 the tool flags that you may be giving up visible quality to compression.
No. Resolution is only 20% of the score, and an upscaled or out-of-focus image will still lose on sharpness, noise and contrast. That is exactly the case this tool is built for: proving that more pixels have not added more detail.
It runs three checks per preset — width within 0.8x to 1.5x of the target, height within the same band, and aspect ratio within 30% of the target ratio — and marks the platform compatible when at least two of the three pass. Platforms re-encode uploads, so treat this as a framing check rather than a guarantee of how the final post looks.