I want to add custom icons to categories dropdown menu (svg files). If i add anything bellow 512×512 it’s really small – not visible. What is the recommended size?
You need to open your SVG icons file with some editor like Sublime Text or default system text editor and add width=”31″ height=”40″ (set your values) attributes to your <svg> tag like it is shown: http://prntscr.com/m4n0qw
Then you will need to re-upload your icons in WordPress Dashboard.