I have also noticed this, and since the fix is to remove the alt text entry, that breaks XHTML validation :(
I have tried every possible way I can think of sneak the alt text item in, such as:
#set($alttext='blar')
$macros.Image("i/img02.gif", "%{alt=$alttext'}")
but to no avail. Any possibility of seeing a patch to fix this, before 2.0?