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.
How the checks combine in 'Fix Everything'
Fix Everything is not a separate optimizer — it simply applies the fixes the checks flagged, and only those. If the format is wrong for the content, it re-encodes to the fitting format. If the dimensions are far beyond screen needs, it downscales. If the file is already well-formed, there is nothing to fix and the honest result is 'no issues found'. It never upscales, never invents detail, and never strips transparency that is actually in use — each fix traces back to a check you can read.
When to run it
The natural moments are right before an upload with limits (a marketplace listing, a CMS, an application portal that rejects files over a few megabytes), before emailing a batch of photos, and on files exported from design software, which are routinely exported at print settings for screen use. Running the check takes seconds per image and costs nothing, so it is worth making it the first step whenever an image is about to travel.
Reading the diagnosis like a person, not a score
The report is deliberately not a grade out of 100. An image can 'fail' the size check and be exactly right for printing, or pass everything and still be the wrong photo. Treat each flagged item as a question — is this file bigger, or in a different format, than its job needs? — and fix only what your actual use calls for. The tool's job is to make the invisible properties of the file visible; the judgment stays yours.
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.
- Run File Doctor before a big upload session — fixing ten images takes less time than one rejected upload.
- Keep your original camera or design files archived; you can re-export and re-check any time, and the check is instant.