Pictures in HTML files in iOS app

Pictures in HTML files in iOS app

I'm very new to iOS development and I'm having an issue with displaying an
image inside HTML file. I successfully display the html file in a webView
but not the images inside it. I have added the png files to the same
folder that I retrieve the html file but neither the
background-image: url(bg1.png);
nor the
<img src="logo.png"/>
seem to work.
I think I've worked out the way to add the external files to iOS app
because I successfully set those pictures as the background for webView,
my issue is the HTML file does not display it. I also tested the file in
several browsers and there's no problem.
Am I writing the paths wrong or is this an even simpler rookie mistake?
Thanks in advance.