Using relative URL's
Try <img src="/page_first/my_image.png"/>
I do a simple web application written in Python using cherrypy and Mako. So, my question is also simple. 
I have one page with URL http://1.2.3.4/a/page_first. Also there is an image that available on URL http://1.2.3.4/a/page_first/my_image.png. And I want to locate my_image.png on the page_first. 
I added a tag <img src="my_image.png"/>, but it is not shown. I looked at web developer tools->Network and saw that request URL for image was http://1.2.3.4/a/my_image.png, instead of http://1.2.3.4/a/page_first/my_image.png.
Why does it happen?
Thanks.