Were you able to get this sorted out? I see a header image at the top left in the sidebar, where it should be:

Let me know if you’re all set.
Hi Kathryn!
Sorry for the late reply. Apologies if I did not made it clear, what I meant was the header for the blog.
It appears when the viewer clicks “blog”.
http://workfromhomefreelancer.com/blog/
But when they get inside the blog post, there’s no more header.
http://workfromhomefreelancer.com/immediately-learn-new-skills-im-always-busy/
The header appears when posted in Facebook, but on Pinterest, its not. I have to use the images inside the blog instead, which aren’t so attention grabbing.
And another question, how do I make it that the blog posts will appear as summary when appeared in “Blog” page? I already checked “blog posts to appear as summary” but its not working.
Hi there – I’m seeing the custom header on both of these pages:
http://workfromhomefreelancer.com/blog/
http://workfromhomefreelancer.com/immediately-learn-new-skills-im-always-busy/
Just to make sure we’re talking about the same thing, here is a screenshot where I’ve circled the header graphic:

If you’re referring instead to the featured image of each specific post, they are not displayed on single posts, only on the blog page – that’s how the theme is designed.
If you wanted to change that, you would need to make a child theme and make some code changes. If that’s something you’d be comfortable with, let me know and I can help you further.
Making a child theme means your changes won’t be overwritten when you update the theme. If you’re new to child themes, you can explore these guides:
http://codex.ww.wp.xz.cn/Child_Themes
http://op111.net/53/
http://vimeo.com/39023468
The header appears when posted in Facebook, but on Pinterest, its not. I have to use the images inside the blog instead, which aren’t so attention grabbing.
If you need fine control over which images are served up when your posts are shared in social media, I recommend using a plugin where you can do that, like WordPress SEO.
And another question, how do I make it that the blog posts will appear as summary when appeared in “Blog” page? I already checked “blog posts to appear as summary” but its not working.
That setting only applies to RSS feeds and other services that rely on the feed. It does not apply to the version of your site viewed in a web browser.
To make this change will also require a child theme. If that’s something you want to pursue, let me know, and you can set it up using one of the guides above. I can give you help with the specific code changes you’ll need at that point.