Programming :: Frameset Target Not Working Properly

I have a webpage in html that uses <frameset> tag. One of the frames is a Table of Contents (toc.htm) that lists a series of images. The other frame is called 'canvas.htm'. My framset is laid out as follows:

<frameset rows="20%, 80%">
<frame src="./banner_sp.htm" ></frame>
<frameset cols="15, 85">
<frame name="toc" src="./toc.htm" ></frame>
[Code]....

The frameset is created properly and I can load the images manually (i.e. I can access the images from my browser and/or image editing tool). The problem comes when I attempt to access the images from the toc.htm frame. Instead of opening the image in the canvas.htm frame, a new window is displayed in my browser, instead of the image being displayed in the target window (canvas.htm). This happens on all of my browsers (firefox, safari, IE7/8 and Opera) on Windows, debian-linux and OS X 10.5/10.6.

If I change my src attribute (in the canvas frame) to toc.htm, I see the Table of Contents (toc.htm) displayed side-by-side until I click on the first drawing in the list. At this point, the frame 'behaves' half-arsed the way I want it to. I have searched on google till I am blue(er) in the face with no luck.