Bicubic is a mathematical interpolation method used in image processing to resize images. It works by considering the closest 16 pixels (4x4 grid) around a target pixel to calculate its new value. This technique provides smoother and more visually appealing results compared to simpler methods like nearest-neighbor or bilinear interpolation. In addition to image resizing, bicubic interpolation is also used in various applications, including computer graphics and digital photography. It helps maintain image quality by reducing artifacts and preserving details, making it a popular choice for software like Adobe Photoshop and GIMP.