title: How do you know the location in pix
body: <p>I'm going to try and ask this the best way I can so sorry if I am not clear. </p>
  
  <p>I am trying to learn css and html. </p>
  
  <p>When it comes to positioning a image, for example <code>top: # px;</code>, how do I know what the pixel location is? Is there a program for that or is it a guessing game? </p>
  
  <p>I hope you can understand my question. Thanks</p>