What File Doctor Actually Checks in Your Images (and Why)
A look inside Convorae's image health-check tool: the four things it inspects, why each one matters, and when 'Fix Everything' won't help.
Most "image optimizer" tools ask you to pick a quality slider and hope for the best. File Doctor takes a different approach: it actually diagnoses what's wrong with an image first, in plain language, then fixes only what needs fixing. Here's what it's actually checking, and why.
Check 1: Is the file format efficient for this image?
A flat-color logo saved as JPEG carries compression artifacts it doesn't need; a photo saved as PNG is often several times larger than the same photo as JPEG or WebP for no visible quality gain. File Doctor looks at what's actually in the image (photo-like gradients vs flat color, presence of transparency) to judge whether the current format fits.
Check 2: Is the file size larger than it needs to be?
Two images can look identical at the same dimensions with very different file sizes, depending on compression settings used when they were saved. This check flags a file that's carrying more bytes than its visual complexity justifies — often the result of a camera's default JPEG quality or an unoptimized export from design software.
Check 3: Are the dimensions bigger than necessary?
A 4000×3000 photo displayed at 400×300 pixels on a webpage is wasting well over 100x the pixels a screen will actually show. This check compares the image's real pixel dimensions against what's reasonable for typical screen use, and flags anything far beyond that.
Check 4: Does it need transparency, and does it have it?
This one cuts both ways: a PNG with no transparent pixels anywhere is a strong sign it should be WebP or JPEG instead (this check feeds directly into Check 1); a PNG that DOES use transparency needs to keep that format (or WebP, which also supports it) — 'Fix Everything' preserves transparency when it's actually present.
Quick tips
- If "No issues found" comes back, that's a real result, not a limitation — it means the file is already reasonably optimized, not that the check didn't run.
- "Fix Everything" only re-encodes format and downscales oversized dimensions — it never upscales a small image bigger, and never adds detail that wasn't there.
- These four checks cover format/size/dimensions/transparency specifically — they don't evaluate visual quality subjectively (like whether a photo is well-composed), which is outside what an automated check can judge.