Issue with Thumbnail Images

Hi.

I would like to be able to choose which images appear as the thumbnail for my blogs. If I choose an image as featured image, the image will also appear in the blog, and it doesn’t seem I can place where in the blog this image appears.

I also noticed that the first image that is added to the blog is the image that becomes the thumbnail image, which is also not good as I want more control over which image appears as a thumbnail.

Thank you for any tips or suggested plugins to solve this issue.