Find visible color outside mapped skin faces
This Minecraft illegal pixel checker inspects an exact 64 × 64 skin PNG and lists every nontransparent pixel that falls outside the UV faces used by the selected Classic or Slim model. It displays the original atlas, creates a second preview with every reported coordinate marked red, and lets you download a CSV report or diagnostic PNG.
“Illegal pixel” is common search language, but it should not be read as a universal game rule. These are visible pixels outside the selected standard UV map. They normally do not appear on the character and may be unwanted background residue, yet a specific launcher, pack pipeline, mod, or renderer can have different behavior. The checker describes atlas structure; it does not issue an official acceptance verdict.
All analysis runs locally. The image, filename, selected model, coordinates, previews, and report never leave the browser.
How to run the check
Upload a PNG that is exactly 64 pixels wide and 64 pixels high, or begin with the first-party example. Select Classic for four-pixel arms or Slim for three-pixel arms. The report recalculates immediately because the effective arm-face map changes with the model.
The source preview preserves the original. The red diagnostic preview is a separate generated copy. A coordinate such as (12, 9) identifies the pixel’s zero-based x and y position in the atlas. The CSV contains one row per finding and can be opened in a spreadsheet, text editor, test script, or asset review system.
Use Download marked preview when a visual handoff is easier than a coordinate list. The marked file is diagnostic artwork, not a repaired skin: red replaces each flagged visible pixel so its location is obvious. Keep the original file and do not import the marked preview by mistake.
What counts as outside the UV map
A 64 × 64 PNG has 4,096 possible pixel positions, but only specific rectangles map to the six faces of each body part and its outer layer. Other locations are padding or unused atlas space. A transparent pixel in unused space is normal. A visible pixel there is reported because it consumes image data without contributing to a standard mapped face.
The checker evaluates alpha. A pixel with alpha zero is ignored even if hidden RGB channel values exist. Any alpha greater than zero counts as visible, including a nearly transparent value. This strict rule helps catch faint residue left by selection tools, antialiasing, erasers, or exports from general-purpose image editors.
The check is different from finding transparent holes inside the body. A missing base pixel is inside a mapped face but has no opacity. Use the full Minecraft skin checker for that structural warning. This page focuses on the opposite condition: visible content outside mapped faces.
Why Classic and Slim can produce different findings
Classic and Slim skins share the same canvas dimensions and most UV regions, but their arm faces have different effective widths. A narrow column that belongs to a Classic arm face can be outside the selected Slim face map, or vice versa depending on the exact region. That is why the model selector is part of the analysis rather than a cosmetic preference.
If you do not know the intended model, use the Minecraft skin model detector and examine its evidence. Detection remains heuristic because transparent or intentionally sparse arm pixels can make the distinction ambiguous. Run both checks when auditing an uncertain asset and compare the coordinate changes.
Common causes of flagged pixels
Background residue often appears after copying a skin from a screenshot, erasing a solid backdrop, or exporting with selection edges. A single forgotten dot in unused space is easy to miss at normal zoom. Drawing tools can also continue a brush stroke beyond a UV rectangle. Templates from unknown sources may include labels, guides, watermarks, or colored region keys on the same canvas.
Another cause is choosing the wrong arm model. The file can be structurally reasonable for Classic and appear to have extra pixels under Slim. A custom renderer may also intentionally use normally unused positions. In that situation, the report is still accurate for the selected standard map, but deleting the pixels may not serve your custom workflow.
What to do after finding pixels
First confirm the arm model and inspect the red preview. If the dots are clearly accidental, use the Minecraft skin background cleaner to create a copy with outside-map pixels cleared. That tool applies the same mapped-region concept and leaves the source unchanged.
If the findings seem connected to valid artwork, compare the original in the Minecraft skin layer viewer and a 2D editor. Never erase coordinates solely because a number is nonzero. Keep a source copy, clean under a new filename, and compare before and after.
For repeatable production checks, download the CSV. It records x, y, and original RGBA values, making review more specific than “the skin has extra pixels.” A designer can locate each point, and a developer can include the list in an asset-quality ticket.
What this tool does not check
The page does not validate account ownership, game edition, server policy, marketplace rules, skin-pack metadata, file signatures, or moderation. It does not identify copyrighted characters, offensive artwork, or visual quality. It also does not guarantee that a standard client will reject a file with flagged coordinates; unused visible pixels are often simply ignored.
Use the Minecraft skin compatibility checker for a Java, Bedrock, and legacy format matrix, and the 64x64 to 64x32 converter only when a legacy export is genuinely required.
Privacy and ownership
The implementation uses browser canvas APIs and has no upload endpoint, account, database, or public gallery. Closing the page clears the active analysis unless you downloaded a report. Inspect only files you own or have permission to use. A technical report does not grant rights to someone else’s artwork.
SkinEditor.org is an independent tool and is not associated with or approved by Mojang or Microsoft.
Frequently asked questions
Does a reported pixel always break a skin?
No. It is outside the selected standard UV faces and usually invisible, but acceptance and rendering depend on the target environment.
Does the checker edit my source?
No. It generates a separate red preview and CSV. The selected file remains unchanged.
Why are coordinates zero-based?
Image APIs and atlas tooling conventionally start x and y at zero, so the top-left pixel is (0, 0).
Can the checker remove the findings?
Use the linked background cleaner for a separate cleaned PNG after reviewing the report.