HI,
The One-click-import(Import Demo Data) only import the image placeholder( the word ‘DEMO’ on grey).
If you want to import the real image. You could use “Import My Saved Data”, please remove all imported content(single posts/pages) firstly:

Click “choose file”,

Pick up the xml file: “default-demo.xml”, you could find the xml in /functions/theme/ folder
Click “Upload file and import”
The page will be shown, set author and attachment, click submit:

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If it doesn’t work, please send your wp-admin(url/user/pass) via
my profile contact form , I’ll log in to check it.
Regards!
Bwsm – uiueux.com – Twitter – Facebook