The JPEG file format is a go-to for most digital images. It’s small enough to transfer quickly, and it can be easily manipulated with popular image-processing programs like Photoshop. It also saves storage space because it discards information that the human eye cannot see. This lossy compression helps the file size shrink to a fraction of its original size.
However, despite the great convenience of this file format, it’s not well suited to images that require precise reproduction or edits. The information in a JPEG file is degraded each time it’s saved and recompressed. This degradation is called “digital generation loss”. It can also happen if the image is altered, such as by cropping, or if different encoding parameters are used.
To avoid this, a lossless image compression format is usually better for these applications. Fortunately, there are many great tools available to Compress Jpeg images without losing quality.
Striking the Right Balance: Tips and Tricks for Optimal JPEG Compression
Compressing JPEG images uses a method known as transform coding, which reduces the number of bits needed to represent an image by eliminating frequencies that the human eye can’t perceive. The result is that the final image has a much smaller MB size than its original form.
The image data is then encoded into a stream of bytes using a Huffman code, and the bytes are decoded back into an image. The Huffman code can be either baseline progressive or baseline sequential. The baseline progressive version uses a table of values similar to the corresponding coefficients in the DCT matrix. The algorithm zigzags through the coefficients in the matrix, encoding and decoding each one with the next value until all the coefficients have been encoded. The result is a smaller file size with an image that appears to the human eye almost identical to the original.