Thanks for your inputs guys! I made it to work using this workaround:

<TD>
  <INPUT type="hidden" name="page">
</TD>
<TD>
  <A href="javascript:do_Submit(1)"><IMG src="page1.gif" ...></A>
  <A href="javascript:do_Submit(2)"><IMG src="page2.gif" ...></A>
  <A href="javascript:do_Submit(3)"><IMG src="page3.gif" ...></A>
  <A href="javascript:do_Submit(4)"><IMG src="page4.gif" ...></A>

  ...

  <A href="javascript:do_Submit(50)"><IMG src="page50.gif" ...></A>
</TD>
[download]

The on the javascript:

function do_Submit(page) {
  var page;
  document.forms[0].page.value = page;
  document.forms[0].submit();
}
[download]

I also confirmed that this wasn't supported in the HTML specs. I just assumed too much when I made the code. But I wasn't able to catch it soon enough since I am always using Firefox