HTML/HTTP/INTARNET BROWSARS

Hay guys, how the hell do HTML/HTTP/Browsers really work? See, i have this one piece of code running, which when you connect to it will return some html code. So you see some nice pretty plain text, yay.

 I do however want it to be able to return images, <IMG SRC...> does not work. As it only bounce back strings of text it fail no matter what i try with that approach. So what should i really return to get an image to display? There have to be some way to toss information to the recepient so that the browser generate a fucking image at the recepients end.

Language i use is ruby(in before rails or eruby) if that helps any.

feels like my head is full of cotton right now, but i guess i've misunderstood how things work.

So my little program do
"session.print <IMG SRC="lulzz.jpg" ALT="some text">"
and when the client get this it request the server for lulzz.jpg. So i have to put together some code which upon request for lulzz.jpg will send the image to client in correct format and so on instead of trying to forcefeed the client said image.