I took a look at your Dads website, it is clean, while it could have more content with a bit different names if it starts to get bigger.
I found it nice, but I wish i could see a row of thumbnails like everyones said, then before you can click that there should be a sideshow button function where its easily visible to someone.
But if we want to look at a specific picture, take us to the picture with a bigger image size. Since it is photography, I like to see the details of photo instead of it being small and having to move into my monitor screen.
[ My explaining sucks so i apologize beforehand if you don't understand a word i said ]
Btw let him know he has some great shots and The reason id like to see higher resolution is because they do look great and some could be some nice wallpapers.
** It works in Opera just fine since i saw TheSchafts post about the compatibility