I'm not sure what you mean by the 'HTML code' of your photo. Once you post your photo online (like through Photo Bucket or Flickr or something), right click on the photo and go to View Image. Copy the URL at the top of the page.
This HTML code will post your image on any website you are creating:
<img src="http://www.yourimageURLhere.com">
Replace the "yourimageURLhere" with the URL you copied from Flickr or Photo Bucket (or whatever source your image was coming from) and you should be good to go.