Hi, after a quick look at this page:
http://www.jqplot.com/tests/line-charts.php[
^] it seems that the graphs are drawn onto a canvas.
If that's the case with your graph too, then I think you're possibly 1/2 of the way there. That is to say, if you get the canvas element, you can call toDataURL on it. This will return a base64 encoded version of the image. You can the set this as an img's source. Once it's an an image and not just a canvas, you can save it.
See here:
toDataURL method[
^]
As an example, if you open the page I linked to, you can find the correct element and give it an id. Once this is done, entering the following into the console will insert a brand-new image onto the page.
{ var img=new Image; img.src = document.getElementById('mTgt3').toDataURL(); document.body.appendChild(img);}
As you can probably tell, it took me a couple of goes to work out what the correct element was.
The graphs are made up of a number of canvas elements stacked ontop of each other - each one just doing part of the job. The one I ended up choosing was the one that holds the blue data line.
The element I ended up using was this one - (its a canvas for the first graph on the page):
<canvas width="468" height="262" style="position: absolute; left: 22px; top: 10px; " class="jqplot-series-canvas" id="mTgt3"></canvas>
Note the id of mTgt3 - I added that by right-clicking the element in the Elements tab of Crome's dev tools and Add Attribute.