How do image compression and text compression work? How are they similar and how are they different?

The primary goal of both image and text compression is to reduce file size and transmission bandwidth while minimizing quality loss. Text compression often employs techniques like dictionary-based encoding (e.g., Lempel-Ziv) where frequently occurring words, phrases, or even character sequences are replaced with shorter codes. This is typically lossless, meaning the original data can be perfectly reconstructed. Image compression, on the other hand, can be either lossless (like PNG) or lossy (like JPEG). Lossy compression achieves higher compression ratios by discarding some image information that is less perceptible to the human eye, such as subtle color variations or high-frequency details. While both methods aim to represent data more efficiently, text compression prioritizes perfect reconstruction, whereas image compression often balances size reduction with acceptable visual fidelity.