The element in my project looks like this...
<* input type="image" name="ick" value="gakkk" src="button.jpg" />
...and the interface to which this form POSTs looks for the ick field. Looks to me like MSIE7 just doesn't send any name/value data in one of these elements when the form is submitted. All the other form fields make it into the POST data, just not the ick/gakkk pair.
Either of the following seemed to make it work as expected:
- turning the input element into a normal type="submit"
- moving the ick/gakkk name/value pair into a hidden input element in the form
*sigh* Just one more stupid thing I have to remember when designing Web applications.