So I saw that there is another post with this same problem but the solution suggested in that post (changing the Image style options) did not work for me. I'm still getting a white background instead of a transparent. Tried displaying the same image in a sidebar and it displays correctly.

Here is a link to the page. Any suggestions are greatly appreciated.

http://www.iomcpatriotcrew.com/officers/

What image and what browser?
Looks fine to me in Safari and FireFox on a mac.

I've tried it on a PC in Chrome, IE and Firefox. It's the image with the 6 pictures in frames. It should have a transparent background with white lettering under the images. When we look at it in the above browsers on a PC the background doesn't show through and the pictures sit on a white background so the lettering doesn't show up.

Just tried it on a mac here and it still doesn't have the transparency that is inherent in the image

go to ato->Style IMAGES->Images in Posts and blank out the settings

Already did that and it doesn't change anything (that was what the original post I referenced suggested). Is it possible there is another area overriding that section?

Yes, looks like you added that into the CSS Inserts also

That did it. Thanks!!!