Fix blog lead image compression

We talked about this a bit before, but it's still happening. It doesn't seem to matter what size the image is, the quality is lowered when it is used as the lead image.

If I put the image in the body of the post, it is okay. But having it in the body of the post does not show from the blog archive, which we want.

See the attached screenshot which shows the difference between what's on the blog and the original file.