Why will my PNG file not open?

PNG support is universal, so the cause is nearly always the file: a truncated download, or another format renamed to .png. Drag it onto a browser to test, and check the header, which should begin with the text "PNG".

What is the difference between PNG and JPG?

PNG is lossless and supports transparency, which suits screenshots, logos and line art. JPEG discards detail to shrink the file, which suits photographs. Re-saving a JPEG as PNG does not recover the detail already lost.

File extensions

How to open a .png file

Portable Network Graphics · Image

Every operating system, browser and image viewer opens PNG files. If yours will not open, the file is damaged, incomplete, or is not actually a PNG despite its name.

What a .png file actually is

PNG is the standard lossless image format, created in 1996 as a free replacement for GIF. It supports full transparency and compresses without throwing away detail, which is why screenshots and logos use it.

Support is universal. That changes the diagnosis: a PNG that will not open is a file problem, not a software problem.

Why it will not open

Three causes cover almost everything. The download was truncated, so the file ends mid-image. The file was renamed from another format and is not a PNG at all. Or Windows Photos itself is misbehaving, in which case any other viewer opens it fine.

Renaming it to an extension you can open will not help: changing the extension does not convert the file, it only changes what Windows tries to open it with.

Step by step

Windows

01Try a different viewer first. Drag the file onto a browser window: if it displays there, the image is fine and Windows Photos is the problem.
02If nothing displays it, check the size. A PNG of zero or a few bytes never finished downloading.
03Check what it really is: open it in HxD and look at the first bytes. A real PNG starts with the byte 0x89 followed by the readable text "PNG".
04If the header says something else, rename the file to match. A JPEG renamed to .png opens once the extension is honest.

macOS

01Double-click. Preview opens PNG natively.
02Run "file image.png" in Terminal to confirm what the file actually is when it refuses.

What usually goes wrong

A partly downloaded PNG looks normal

The file has the right name and icon whether it downloaded fully or stopped at 40%. Some viewers show the top portion and grey below, which is the clearest sign that the data is simply missing.

Programs that open .png

Our pick, in order. Every one links to the publisher's official download URL and the SHA-256 hash of the installer. Once you have downloaded it, you can check the file against our index before you run it.

If you end up downloading one of these from somewhere other than the publisher, what you can and cannot verify about that is worth two minutes.

Also registers .png in its manifest

Taken straight from publisher manifests. Some of these handle the format for a narrow purpose rather than as their main job.

Common questions

Why will my PNG file not open?: PNG support is universal, so the cause is nearly always the file: a truncated download, or another format renamed to .png. Drag it onto a browser to test, and check the header, which should begin with the text "PNG".
What is the difference between PNG and JPG?: PNG is lossless and supports transparency, which suits screenshots, logos and line art. JPEG discards detail to shrink the file, which suits photographs. Re-saving a JPEG as PNG does not recover the detail already lost.