Which image format uses a lossy form of compression meaning that some original image information is lost and cannot be restored?

• A. .PNG
• B. .JPEG/.JPG
• C. .GIF
• D. .BMP

Answer: (B)

Lossy compression reduces a file’s size by discarding some image information, so the exact original can’t be perfectly restored after compression. JPEG is built around this idea: it uses a process that quantizes data and throws away detail the human eye tends to overlook in photographs, which yields much smaller files at the cost of some quality. When you push JPEG to high compression, you can see artifacts such as blur or blocky edges.

The other formats typically use lossless methods, meaning no data is discarded and the original image can be perfectly reconstructed. PNG preserves every pixel through lossless compression, GIF uses lossless LZW with a limited color palette, and BMP usually stores image data uncompressed. So they don’t involve lossy compression by default.