I recently saw how the old Safari 2 browser sees my website.

Even though my site has a zero mistake validation, Safari 2 shows the background of the iFrame element as white.

I set it to the same color as the surrounding area, to almost black.

Now, in Safari 2, the background is white. Which looks terrible for the photos, as the white is blinding.

Anybody had experiences like this?

Why are you worried about such an old version of Safari ? For the most part, people who use Safari are more likely to have a much more recent version.