No hard decision
With so many platforms and icons, it's hard to know exactly what you should do. What are the dimensions of favicon.ico? How many Touch icons do I need? RealFaviconGenerator did the reseach and testing for you.
Color conversion, bandwidth calculator, photo/video bitrate/filesize, aspect ratio/composition/dept-of-field, bpm, html charmap
Simple, free, fully responsive one-page sites for pretty much anything
Fast web pages for everybody.