> best results with Triangle also known as bilinear interpolation
Just no. Use bilinear only when you need very fast resizing and don't care about quality much. Lanczos and sinc [1] filters are considered "best" for wide range of images (no visible blurring or sharpening, almost no moire effects), but they are also among slower ones. Use Catmull-Rom when images need to be sharpened a bit. (See [2] for comparison and scripts) There's also faster and less buggy fork named GraphicsMagick [3]
[1] https://en.wikipedia.org/wiki/Sinc_filter