How to mass convert PNG to JPG (Tutorial)

Handling a vast collection of PNG images? Converting them to JPG in bulk can be extremely beneficial, especially if you need JPGs for various purposes.

You can read, write and convert PNG files in Java with JDeli, our pure Java library.

PNG (Portable Network Graphics) is a format known for its lossless compression and is widely used across various devices and platforms. Converting PNG images to JPG can significantly reduce file size, making them easier to store and share without compromising too much on quality.

In this article, I’ll guide you through the process of using Java to change PNG files to JPG format with JDeli, ensuring your images are accessible. JDeli is the best enterprise-level Java image library for image manipulation.

Mass convert PNG to JPG using Java

1. Download the JDeli trial jar.
2. Process image if needed (scale, sharpen, lighten, watermark, etc)
3. Write out BufferedImage as JPG image file

BufferedImage bufferedImage = JDeli.read(new File("pngImageFile.png"));

// Read PNG image into Java


bufferedImage = operations.apply(BufferedImage bufferedImage);

// Process image (Optional)


JDeli.write(bufferedImage, "jpg", new File("jpgImageFile.jpg"));

// Write out BufferedImage as JPEG image file

Export PNG to JPG in one line of code

With the JDeli.convert() method you can save PNG as JPG in just one line of code.

Using File

JDeli.convert(File inFile, File outFile);

JDeli.convert(InputStream inputStream, OutputStream outputStream, "jpg");

byte[] outputData = JDeli.convert(byte[] inputData, "jpg");

JDeli.convert(File inFile, EncoderOptions outputOptions, File outfile);

How to bulk convert PNG to JPG from the command line

You can turn PNG to JPG using command line or bash, bat, and PowerShell scripts. This method also enables JDeli to be invoked from any programming language that supports creating a child process.

java -jar jdeli.jar –convert jpg "inputFileOrDir" "outputDir"

In this tutorial you learned how to bulk convert PNG to JPG in bulk. JDeli has PNG support for reading, writing and compression as well, you read our documentation to find out more.

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

// 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);