You posted in the SEO section - I don't think the size of logo in pixels or in kb matters. Although I guess if it's too big or too small it might be a flag that you're a newbie who doesn't know how to build a page properly.
There is no as such standard size defined for logo but it should be most importantly in vector form so that even if zoomed in or zoomed out it should not get distorted in pixels. Quality should be maintained as the original form in all screen resolutions. While incorporating logo in the website some proper coding is done to display it properly.
There is no as such standard size defined for logo. Below is a list of standard dimensions based on more popular sizes with mobile options Logos for Websites: Favicons: 16×16, 32×32, 48×48 Website Horizontal 250 x 150 350 x 75 400 x 100 Website Square or Vertical: 160 x 160