JPEG is a file format standard for digital image compression.

It uses a technique called Discrete Cosine Transform (DCT) to convert an image into a series of coefficients, and then quantizes, encodes and compresses these coefficients, thus reducing the size of the image file. JPEG is widely used in various fields, such as photography, design, web page making, printing and so on. Because of its high compression ratio and good image quality, JPEG has become one of the widely used standards in the field of digital image processing.

JPEG is a lossy compression format, which means that some image data will be discarded in the compression process to achieve a higher compression rate. Therefore, JPEG compressed images may not be fully restored to the original quality after decompression. In contrast, lossless compression formats (such as PNG) will retain all the data of the original image, but the file size may be larger.

Important information and details of JPEG format

1, compression level: JPEG has many compression levels, from the highest quality (low compression) to the lowest quality (high compression). Higher quality setting will get better image quality, but the file size is also larger; Conversely, a lower quality setting will produce a smaller file, but the image quality may be degraded.

2. Color depth and color space: JPEG supports a variety of color depths and color spaces, such as RGB and CMYK. These settings will affect the color representation and file size of the image.

3. Compatibility: Due to the wide use of JPEG, most image editing software, browsers and devices support JPEG format, which makes it one of the preferred formats in digital image processing and network transmission.

4. Copyright and security: JPEG format supports embedding copyright information and watermark, which makes it possible to protect the copyright of images. In addition, some new JPEG variants also support encryption and digital signature, which enhances the security of files.