Content img problem

I ran the wordpress theme test on my site which is using a twenty ten child theme, and noticed the “Centered Image with Caption” is messed up.

If I disable width:auto; in #content img in firebug, it fixes it, not sure how to add that to my child theme.
https://test.zeaks.org/uncategorized/images-test/ is what it looks like,
https://wpthemetestdata.wordpress.com/2008/09/03/images-test/ is what it should look like.

There’s also an issue with the caption and border (I changed it to black so it’s easier to see) the bottom border under the cation won’t show, the image also breaks out of the border.

Seemed simple to fix, but after playing around with it for an hour, I haven’t figured it out.