Used to adjust the filter algorithm used when resizing images. Different filters experience varying degrees of success with various images and can take significantly different amounts of processing time. ImageMagick uses the LanczosFilter by default since this filter has been shown to provide the best results for most images in a reasonable amount of time. Other filter types (e.g. TriangleFilter) may execute much faster but may show artifacts when the image is re-sized or around diagonal lines. The only way to be sure is to test the filter with sample images.