Featured Image Thumbnails Appearing Incorrectly

Instead of just appearing in the recent post widget and next to the post when its category is clicked, the thumbnail of the featured image appears inside the actual blog post, next to the picture.

So there's now 2 images in the post instead of just one. Please advise ASAP so that my client can launch her site on time. The time being in the next 3 days.

The same problem!!! How to remove the thumbnail from the records??? To pictures are not duplicated??? If you want I can show photo of what it looks like and what needs to be fixed!