It should be trivial to reauthor .swf content to modern web standards.

https://github.com/sv1sjp/flash-swf-to-html5-toolkit

Macromedia Flash 1.0 was released the same year as the Space Jam website, I don't think it used .SWFs. In fact I don't remember .SWFs being common until 2002-2003 (but that's my biased viewpoint, since that's when I discovered Newgrounds.)