Hi,

You've asked a very interesting question that has certainly been asked before. Unfortunately using vphantom etc isn't going to work if you need to move the image downwards.

We do calculate the baseline of an image, you can see this if you use:

http://latex.codecogs.com/gif.json?-inline \frac{x}[y}

which gives:

ParseEqn({ "latex": { "type":"gif", "equation":"\\frac{x}[y}", "site":"unknown",
"file":"1d09ff81ad2211e00b9ffa4ded627666.gif",
"url":"http://www.codecogs.com/eq/1d/1d09ff81ad2211e00b9ffa4ded627666.gif", "width":"17", "height":"22", "baseline":"9" } });

We do have some trial code

Which searches an html pages (just like latexit.js here http://www.codecogs.com/latex/htmlequations.php) however we've never been particular happy about the performance.

If you've time to work on this, then we'd be very happy to receive suggestions