How to read PNG files in Java

In this article, I will show you how to read PNG files in Java. We also have a related article covering how to write PNG files in Java.

As part of a separate project to provide customers with a solution to provide an easy way to convert PDF to PNG files in our JPedal software, we wanted better PNG support than we could find in ImageIO and other image libraries. So we wrote our own implementation and made it available as part of JDeli.

How to read a PNG image in Java with ImageIO

1. Create a File handle, InputStream, or URL pointing to the raw PNG image.
2. ImageIO will now be able to read a PNG file into a BufferedImage. This syntax is like so:

   BufferedImage image = ImageIO.read(pngFileOrInputStreamOrURL)

How to read a PNG image in Java with JDeli

1. Add JDeli to your class or module path. (download the trial jar).
2. Create a File handle or InputStream pointing to the raw PNG image. You can also use a byte[] containing the image data.
3. Read the PNG image into a BufferedImage

   BufferedImage image = JDeli.read(pngFile);

Why do developers choose JDeli over free alternatives?

1. Works with newer image formats such as AVIF, HEIC, JPEG XL, WEBP (AVIF next release) that are not supported in Java.
2. Better support than alternatives for JPEG, PNG, TIFF.
3. Process images up to 3x faster than ImageIO and other Java image libraries.
4. Prevent JVM crashes caused by native code in other image libraries such as ImageIO.
5. Image security as JDeli processes images on your servers with no calls to any external system or third party library.

// Read an image
BufferedImage bufferedImage = JDeli.read(dicomImageFile);

// Read an image
BufferedImage bufferedImage = JDeli.read(heicImageFile);

// Write an image
JDeli.write(bufferedImage, "heic", outputStreamOrFile);

// Read an image
BufferedImage bufferedImage = JDeli.read(jpegImageFile);

// Write an image
JDeli.write(bufferedImage, "jpeg", outputStreamOrFile);

// Read an image
BufferedImage bufferedImage = JDeli.read(jpeg2000ImageFile);

// Write an image
JDeli.write(bufferedImage, "jpx", outputStreamOrFile);

// Write an image
JDeli.write(bufferedImage, "pdf", outputStreamOrFile);

// Read an image
BufferedImage bufferedImage = JDeli.read(pngImageFile);

// Write an image
JDeli.write(bufferedImage, "png", outputStreamOrFile);

// Read an image
BufferedImage bufferedImage = JDeli.read(tiffImageFile);

// Write an image
JDeli.write(bufferedImage, "tiff", outputStreamOrFile);

// Read an image
BufferedImage bufferedImage = JDeli.read(webpImageFile);

// Write an image
JDeli.write(bufferedImage, "webp", outputStreamOrFile);