[charlie_brown]

sorry for that, I re-saved this chart in jpeg and it is approx. 160KB. is it ok?
I tried Image Optimizer, but was unsatisfied with results.

No, that's too big still. As that's the equivalent of 8 images posted by everyone else. The tinypng link is your best bet if you don't have photoshop. But you can also reduce the file size by reducing the size of the image as currently it's 2562 pixels wide. Which is almost double the majority of people's screen sizes that visit the site. So try taking that down to a max of 1400 pixels and save as png-8 format if you can.

ok, thank you.