Why does my PNG show a black background in one program but a chequerboard in another?

The program showing black is likely ignoring the alpha channel and displaying the underlying colour values. The chequerboard indicates the alpha channel is present and the file is fine.

Can I get the transparency back after saving a PNG as JPEG?

No. JPEG has no transparency, so the conversion replaced the transparent areas with a solid colour. That colour data is now part of the image and cannot be separated out again.

What does a chequerboard pattern in my editor mean?

A chequerboard pattern is a standard way editors show that a pixel is transparent. If you see it, the alpha channel is working and the PNG transparency is intact.

Is it possible to have a PNG that is corrupted but still shows transparency?

Yes. A PNG can have structural corruption that prevents it from opening, yet the alpha channel data may still be present. A repair tool may be able to fix the structure and recover the transparent areas.

PNG Transparency Turned Black or White: Why It Happens

Open a PNG, see a black or white block where the transparency should be, and the first instinct is corruption. That is not always the case. The symptom happens in two distinct ways. A viewer or export setting ignores the alpha data. Or a conversion permanently deleted it. This guide helps you tell the difference, then tells you what to do next.

How PNG Stores Transparency

PNG handles transparency through two methods. The first uses an alpha channel, present in colour types 4 (greyscale with alpha) and 6 (truecolour with alpha). Each pixel gets a transparency value from fully transparent to fully opaque. The second method uses a tRNS chunk, which works with palette images and single-colour transparency. In both cases, fully transparent pixels still hold colour values. If a viewer or editor ignores the alpha data, it displays those hidden colour values. Those values are often black or white. That is why lost transparency can appear as a solid background even when the file itself is intact.

When it is a Viewer or Export Issue

Many programs display a chequerboard pattern to indicate transparent pixels. If you see a chequerboard in your image editor, the alpha data is present and working. The problem is limited to the program you are using to view or export the image.

Viewer Problems

Some image viewers do not render the alpha data. Older ones, and those built into operating systems, are the worst offenders. They show the underlying colour values instead. This gives the appearance of a black background instead of transparency even when the file is correct.

Export and Conversion Problems

Export a PNG to a format that does not support transparency, and the alpha data is replaced with a solid colour. JPEG has no transparency. Converting PNG to JPEG replaces transparent areas with a solid fill. Some messaging and social apps convert uploaded PNGs to JPEG without warning. The result is a file where transparent areas show white or black because the alpha data was stripped during conversion. Download the image afterwards, and the transparency is gone for good.

How to Check If the Alpha Channel is Still There

Test whether the alpha data is corrupted or the file is intact. Use a basic image editor that shows transparency. Look for a setting that toggles the alpha display. If the editor shows a chequerboard pattern, the alpha data is present. If the background appears solid, try these steps:

Open the image in an editor that supports layers and transparency.
Check the image mode or colour type. An alpha channel should be listed.
Add a new layer behind the image and fill it with a bright colour. If the transparent areas show that colour, the alpha data is working.

If the alpha channel survives, a rebuilt PNG keeps transparency. Save a new copy from the editor. The transparent areas remain. If a conversion discarded the alpha channel, it cannot be recovered. The pixel data for transparent areas was replaced with a solid colour value.

When Transparency is Actually Lost

Confirmed the alpha channel is missing? The file has been permanently altered. This happens when a program or service saves the PNG without the alpha data. Common scenarios include:

Saving a PNG after opening it in software that does not support alpha channels.
Uploading a PNG to a messaging or social app that converts the file to JPEG internally.
Using an export preset that strips alpha data to reduce file size.

In these cases, the background colour that replaced transparency is now part of the image. You cannot restore the original transparent areas. The pixel information for those areas is gone. This is different from a temporary display issue where the file itself is correct.

What Can Be Done About a Corrupted PNG

If the alpha channel is present but the file fails to open or displays incorrectly, the PNG may have structural corruption. An incomplete download or a transfer error can cause this. A repair tool may be able to reconstruct the file structure. But if a conversion removed the alpha data, no tool can recreate it. The missing information is not hidden in the file. It was discarded. For files where the alpha data survives but the file is unreadable, open the PNG in an editor that ignores minor errors. If that works, save a clean copy. As a last option, a dedicated PNG repair tool can attempt to rebuild a corrupted file. It cannot recover an alpha channel that was never saved.

Preventing Transparency Loss

Stop transparent PNGs showing white or black in the future. Keep these points in mind:

Always keep a master copy of your PNG with the alpha channel intact before exporting to other formats.
Check the export settings in your image editor. Ensure the alpha channel is included.
Messaging apps and social platforms often strip transparency. Download the original file from your device, not from the app.
When sharing a PNG that must keep transparency, use a file transfer service that preserves the original format.