It doesn't matter whether the page you display the picture in is a JSP page or ordinary HTML page.
The "trick" is to simply use an HTML image control but to specify a JSP-based URL.
That is, something like:
<img src="http://www.yoursite.com/getImageFromDB.jsp?id=778" />
There are MANY possible variations on the form of the URL. You might use URL rewrites, for example, to have a "pretty" looking url such as:
<img src="http://www.yoursite.com/image/778" />
where in actuality, behind the scenes, that is transformed into the first URL I showed.
So then what you have to do is to write JSP code to retrieve the BLOB from the DB and send it as a binary stream to the browser. And there are many ways to do that. I think you could google for solutions a lot faster than I could write one for you. You shouldn't need more than about 20 or 30 lines of code to do this, by the way.