This looks like a listing that you imported from eBay using the “Import from My eBay” import function.
The problem with listings imported from eBay is that the whole source code of the item description gets downloaded. This includes the code for the listing design and the embded images (image URLs).
The best way to fix it is copying the description text, switch to editor mode, delete the entire description and paste the description back into preview mode:
in Preview mode copy the whole text from the item description (cmd-a, cmd-c)
switch to Editor mode, clear/delete the item description field there.
Paste in the previously in step #1 copied text (cmd-v).
switch back to Preview mode. You can format your item description text here and also add images and select a design as usual.
This will generate clean content and use the latest design version and image links if you start/revise the listing.