képtömörítés

Képtömörítés refers to the process of reducing the file size of digital images. This is achieved by either removing redundant information or by approximating the data in a way that a human eye can still perceive the image with acceptable quality. The primary goal of képtömörítés is to decrease storage space requirements and to speed up data transmission, especially over networks.

There are two main categories of képtömörítés: lossless and lossy. Lossless compression techniques, such as those used in PNG or GIF formats, reduce file size without any loss of image quality. This is done by identifying and eliminating statistical redundancy in the image data. When a losslessly compressed image is decompressed, it is identical to the original.

Lossy compression, on the other hand, achieves significantly higher compression ratios by discarding some image data that is considered less important to human perception. JPEG is a prime example of a lossy compression format. While it results in smaller file sizes, repeated saving or aggressive compression can lead to a noticeable degradation in image quality, characterized by artifacts like blurring or blockiness.

The choice between lossless and lossy compression depends on the intended use of the image. For applications where perfect fidelity is crucial, such as medical imaging or archival purposes, lossless compression is preferred. For web use, sharing on social media, or where file size is a major concern, lossy compression is often the more practical choice, balancing quality with efficiency. Various algorithms and standards exist within these categories, each with its own strengths and weaknesses.