Another thing you can do is crop the photo instead of resizing.
I won't post the original pic as it is too large but I will post the info.
Original photo size
Width 2048 pixels
Height 1536 pixels
Resolution 180 pixels per inch
After adjustments the file size went up to over 9 megs.
Optimizing at 100% would put it at 1.6 megs.
Optimized for the web at 50% quality equals 416.2K kb which means it should load in 149 seconds @ 28.8 kbps (dial up speed).
Since the photo hosting site I use requires 100K or less I usually reduce my photos toabout 75K for faster loading.
Reduced to:
Width 640 pixels
Height 480 pixels
Resolution 90 pixels per inch
Optimized for the web at 50% quality equals 50.02K which means it should load in 19 seconds @ 28.8 kbps (dial up speed).

Cropped to:
Width 640 pixels
Height 480 pixels
Resolution 90 pixels per inch
Optimized for the web at 50% quality equals 49.56K which means it should load in 19 seconds @ 28.8 kbps (dial up speed).

You will notice that the numers (width/height/resolution/optimization) are virtually identical for both photos, but by cropping I am able to give the illusion of enlarging the photo.
Not always the cleanest looking way to do it, but you can see more detail and they load fast.