Kuvakompressiokäytännön

Kuvakompressio, or image compression, refers to the process of reducing the amount of data required to represent a digital image. This reduction is achieved by encoding the image data in a more efficient format, thereby decreasing file size. The primary goals of image compression are to save storage space and to reduce the time and bandwidth needed for transmitting images over networks.

There are two main categories of image compression: lossless and lossy. Lossless compression techniques reduce file size without any loss of image quality. This is achieved by identifying and eliminating statistical redundancy in the image data. When a losslessly compressed image is decompressed, it is an exact replica of the original. Common examples of lossless compression algorithms include PNG (Portable Network Graphics) and GIF (Graphics Interchange Format).

Lossy compression, on the other hand, achieves greater file size reduction by discarding some of the image data that is considered less perceptible to the human eye. While this results in a smaller file, it also leads to a degradation of image quality. The degree of quality loss can often be controlled by the user. JPEG (Joint Photographic Experts Group) is the most widely used lossy compression format, particularly for photographs. The trade-off between file size and image fidelity is a key consideration when choosing between lossless and lossy compression methods, depending on the specific application and desired outcome.