Transparency, or a picture of it
A real transparent PNG stores an alpha value for every pixel, and the squares you see are your viewer's way of showing “nothing here”. A fake one stores no transparency at all: someone saved a screenshot of the editor, squares included, and gave it a .png name. Converting the fake to JPG keeps the squares on any background, because there is nothing transparent for a background to go under.
The Chequer tab opens first and checks the file the moment it is open, using the pixels at full resolution up to four megapixels so the cell edges are the file's own.
What the check cannot do
- Remove a painted chequer. That is planned; until then the page says so rather than guess.
- Catch a chequer that has been resized or blurred so the cells are no longer clean squares.
- Know whether a picture with a plain grey border was meant to have one.
Questions about checkered PNGs
- Why does my transparent PNG show grey and white squares everywhere?
- Usually because it is not transparent. Many image-search results and free-download sites serve a picture of a transparent PNG: the grey-and-white chequer that editors draw behind transparency has been painted into the pixels. Every app then shows the squares, because they are the picture.
- How does this page tell?
- It checks three things: that no pixel in the file is transparent; that the border is mostly two neutral greys, one lighter than the other; and that those greys alternate in square cells of one size along both edges. All three together are a painted chequer. The panel says which test failed when it is not one.
- Can it remove the squares?
- Not yet. Taking a painted chequer out reliably needs care where the artwork's own colours match the squares, and it is not built. The dependable fix is the real file: download it again from its original source, or export it with transparency switched on.
- What if my PNG really is transparent?
- Then the squares are drawn by your viewer, not stored in the file — this page draws them too, behind the PNG side of the stage. The panel says how much of the picture is transparent, and the matte decides what replaces it in the JPG.
Next steps
- Fake transparent PNGsWhere they come from and how to find the real file.
- Transparent PNG to JPGFor a PNG that really is transparent.
- Why a PNG turns blackThe other common surprise with transparent files.
