What is the JPEG format?

Setting a JPEG Format

The JPEG format, an acronym for Joint Photographic Experts Group, is a type of image file that uses a lossy compression technique. Created in the early 1990s, it was designed to reduce file size while maintaining acceptable visual quality. This compression works by removing some data from the image, which greatly reduces the amount of storage space required. If some visual quality is sacrificed, this makes the JPEG especially well-suited for uses where file size is crucial, such as viewing on the web or sending images by email. The JPEG format has thus become a standard for digital photos and images intended for various applications.

• What is the difference between JPG and JPEG?

In reality, there is no difference between these two terms. Both refer to the same image format. Historically, JPG has been a variant of the JPEG name. In early versions of Windows, file extensions were limited to three characters, so “JPEG” has been abbreviated to “JPG”. On newer systems, such as macOS or modern versions of Windows, files can have either extension without any functional difference.

• JPEG 2000: an evolution of JPEG

JPEG 2000 is an improved version of the JPEG format, developed to provide better image quality and more efficient compression. Unlike traditional JPEG, JPEG 2000 uses lossless compression, which means the image can be compressed without any degradation in quality. However, despite its advantages, JPEG 2000 was unable to replace the standard JPEG. Reasons include limited compatibility with existing software and slower adoption by developers and users.

How to use the JPEG format

The JPEG format is very versatile, but to get the most out of it, it is essential to understand when and how to use it. The JPEG is ideal for complex photos and images with many color gradients. However, for images that require transparency or maximum lossless quality, formats such as PNG or TIFF are preferable. Also, for images intended for printing, it is important to check the resolution of the image. JPEG can compress files significantly, but sometimes this can be done at the expense of the detail required for high-quality printing. In this case, it might be a good idea to use an uncompressed format, such as TIFF, or to work with a high-resolution version of the JPEG, such as JPEG 2000.

In addition to quality and resolution considerations, it is also vital to consider the management of information associated with JPEG files, especially in business contexts or on websites. This makes metadata such as author, creation date, and copyright management possible when using JPEG images. This is where XML (eXtensible Markup Language) comes in. XML is frequently used to structure and transport this metadata, which facilitates better organization and easier integration of images into content management systems or databases.

Advantages and disadvantages of JPEG format

One of the main advantages of JPEG format is its ability to significantly reduce the size of image files, making it ideal for mass image storage, fast sending of photos over the internet, and fast viewing on websites. Due to its wide compatibility, JPEG format is supported by almost all image viewing software, digital cameras and online platforms. In addition, JPEG compression is adaptable, allowing the level of compression to be adjusted to specific file-size and quality requirements, providing the best balance between the two.

However, JPEG compression also has significant drawbacks. The main one is loss of quality due to lossy compression, which can be especially visible in images with subtle color gradients or fine details. Each time a JPEG file is re-saved after modification, a new compression is applied, causing progressive degradation of the image. Also, JPEG does not support transparency, so it is limited for certain types of graphics. Finally, it is not well-suited to images with sharp text or lines, where compression can cause unwanted blurring and distortion.