I second hyperlogic's suggestion (http://www.codecogs.com/latex/eqneditor.php) in that you can get the image using a GET url, e.g. http://latex.codecogs.com/gif.latex?%5Cint_%7B0%7D%5E%7B%5Cinfty%20%7D%20x%5E%7Bt%7D%20dt gives:
The main page helps you get the encoded url.