I have 2 images on the topic page: one above the title and the other one in the main body of the post.
e.g., http://primetutoronline.com/difficult-to-learn

Is it possible to have only 1 picture in the post?

have you made any changes to the 'single.php' virtual template?

Yes, I have, but then I used the "Reset All" button

well I imported your settings, see the two images, did a reset all and now only see one image.

It seems that the "Reset All" button doesn't work by me then... I click on it but nothing changes. What should I do?

Go look at the virtual template and see I'd you have a line with bfa_thumbnails in it, if so remove it.

Finally! It worked! Thank you very much! Now I have only 1 picture.
http://primetutoronline.com/difficult-to-learn