Which file format is typically used for web images that require transparency?

The PNG file format is commonly used for web images that require transparency because it supports an alpha channel, allowing for varying levels of transparency. This capability enables designers to create images that have transparent backgrounds or nuanced edges, which is important for layering images seamlessly over backgrounds without a visible boxy or solid background.

In contrast, JPEG does not support transparency at all, making it unsuitable for images needing transparent areas. GIF does support transparency, but it is limited to a single color being fully transparent and does not allow for varying degrees of transparency, which can restrict the visual quality and flexibility of the image. TIFF is typically used for high-quality images and is not generally suitable for web use due to its larger file size and lack of support by all web browsers, making it impractical for web-based applications.

The PNG format's ability to maintain high image quality while allowing for transparent backgrounds makes it an ideal choice for web graphics, playing a crucial role in modern web design.