PNGkomprimeringsnivå

PNGkomprimeringsnivå refers to the level of compression applied when saving an image in the Portable Network Graphics (PNG) format. PNG is a lossless image format, meaning no image data is lost during compression. However, the compression process itself can be adjusted, influencing the final file size and the time taken to compress the image.

There are typically 9 levels of compression available for PNG files, often ranging from 0 to 9. A compression level of 0 means no compression is applied, resulting in the largest possible file size but the fastest saving time. Conversely, a compression level of 9 offers the maximum compression, leading to the smallest file size but requiring the longest processing time. Intermediate levels provide a balance between file size reduction and compression speed.

The actual compression algorithm used in PNG is DEFLATE, which is a combination of the LZ77 algorithm and Huffman coding. The different compression levels adjust the parameters of this algorithm, such as the search window size for repeated sequences in LZ77. Different PNG encoding tools and libraries may offer slightly different implementations or interpretations of these levels.

Choosing the appropriate PNGkomprimeringsnivå depends on the intended use of the image. For web use where faster loading times are crucial, a higher compression level (e.g., 6-9) is often preferred, even if it takes a bit longer to save. For archival purposes or when disk space is not a concern, a lower compression level might be acceptable. Many modern image editing software and web optimization tools automatically select a suitable compression level or allow users to fine-tune this setting.