Image appears twice when uploaded

I am having an issue with uploading pictures to my post.

I upload pictures into the media library as directed by the WordPress instructions.

I always want my image to appear at the top of my post. On my published post on the home page, the image keeps appearing twice: one larger image and a image picture below it. But if you click to go to the post, only one image will appear: the smaller image.

The only thing that has been working is to upload the image onto my post, then delete it. Somehow the image is still visible on the homepage, but there is no image when you click to go to the post. (This is how my blog is now: http://thesproutingseed.com) (http://thesproutingseed.com/so-many-labels/)

I am really confused. Can anyone explain to me what I am doing wrong and how I can fix this?

Thanks!