What is a recent file format that renders continuous tones and displays transparency within an image file?

A recent file format that supports continuous tones and transparency is the PNG (Portable Network Graphics) format. Developed in the mid-1990s, PNG uses lossless compression and allows for variable transparency levels through an alpha channel, making it ideal for web graphics and images requiring high quality without artifacts. It has largely replaced GIF for many applications due to its broader color support and ability to handle transparency effectively.