Hey Dominic,
Before I can answer your question, I would like to confirm something.
After getting a second opinion from my colleague, it's possible that I misunderstood your main issue. So I would like to reconfirm your issue, when you say images are randomly dropping off the site, do you mean that the height of the images are not in line/different heights? Or do you mean the blog images are not correct/previously has real image and suddenly gone missing?
Refer link for reference.
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http://take.ms/LPBgn)
If the issue is with the height, this can be fixed by applying some css codes. If it's the other issue(cover image missing from the post), then this requires more thorough investigating.
Let us know so we can get a confirmation on the issue, thanks.