May 20, 2023
JPEG (Joint Photographic Experts Group) is a lossy image compression format that is widely used on the web. It was created in 1986 by the Joint Photographic Experts Group, a committee of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC).
JPEG is best suited for compressing digital photographs and other complex images with many colors and gradients. It uses a lossy compression method, which means that some image data is discarded in order to reduce the file size. This results in a reduction in image quality, but the loss is usually not noticeable to the human eye at typical web resolutions.
JPEG was created to address the need for a standard image compression format that would allow photographs and other complex images to be efficiently transmitted over the internet. Before JPEG, there were several proprietary image compression formats, each with their own advantages and disadvantages. This made it difficult for web developers and designers to create web pages with consistent image quality and file sizes.
JPEG solved this problem by providing a standardized compression format that could be used by anyone, regardless of the software or hardware they were using. This allowed web developers to create web pages with high-quality images that would load quickly and consistently across different devices and platforms.
JPEG is the most commonly used image format on the web, and it is supported by all major web browsers and image editing software. It is used for a wide range of web content, including photographs, graphics, and illustrations.
To create a JPEG image, a digital photograph or other complex image is first converted into a bitmap format, where each pixel is represented by a specific color value. The image is then compressed using a JPEG compression algorithm, which reduces the size of the image by discarding some of the color information.
JPEG compression is lossy, meaning that some image data is permanently removed in the process. This can result in a loss of image quality, especially if the image is compressed too much. However, by adjusting the compression level, it is possible to find a balance between image quality and file size that is suitable for a particular use case.
When saving a JPEG image, it is important to consider the compression level and other settings in order to achieve the desired balance between image quality and file size. Most image editing software, including Adobe Photoshop and GIMP, provide options for adjusting these settings.
Comparison with other image formats
JPEG is not the only image format used on the web. There are several other formats, each with their own advantages and disadvantages. Here are some of the most common image formats and how they compare to JPEG:
PNG: PNG (Portable Network Graphics) is a lossless image format that supports transparency. It is best suited for images with sharp lines, text, and other elements that require high image quality and no compression artifacts. However, PNG files are often larger than JPEG files, making them less suitable for large photographs and other complex images.
GIF: GIF (Graphics Interchange Format) is a lossless image format that supports animation. It is best suited for simple graphics and images with few colors, such as logos and icons. However, GIF files are limited to 256 colors, making them less suitable for photographs and other complex images.
WebP: WebP is a relatively new image format that was developed by Google. It uses both lossy and lossless compression, and is designed to provide better compression than JPEG and PNG. However, it is not yet widely supported by web browsers and image editing software.