Quoted from the Photoshop help files Bilinear for a medium-quality method. Bicubic for the slow but more precise method, resulting in the smoothest tonal gradations. Bicubic Smoother when you're enlarging images. Bicubic Sharper for reducing the size of an image. This method maintains the detail in a resampled image. It may, however, over-sharpen some areas of an image. In this case, try using Bicubic.