What is the main difference between lossy and lossless compression?

The main difference between lossy and lossless compression lies in how they handle the data within files. With lossy compression, certain bits of data are permanently removed to achieve a smaller file size. This type of compression is commonly used for media files like images, audio, and video, where a slight loss of quality is acceptable for the sake of reducing the storage requirements and bandwidth usage. The key aspect of lossy compression is that once data is removed, it cannot be restored, making this approach suitable for applications where perfect fidelity is not critical.

In contrast, lossless compression retains all of the original data, allowing the exact original file to be reconstructed from the compressed version without any loss of quality. While lossless compression methods can reduce file size, they typically do not achieve the same level of size reduction as lossy techniques, especially for larger files. Understanding this distinction helps in selecting the appropriate compression method based on the use case and the importance of maintaining data integrity.