That site shows that it's in maintenance mode.
Zen Cart 2.1.0 added a new setting in Configuration // Images: Additional Images matching pattern. On a fresh install, that setting is forced to strict -- while the pre-zc210 default is legacy.
I'm guessing that (a) while the zc210 installation was a fresh install, that additional images were present in the site using the 'legacy' naming convention and (b) that IH has not (yet) been updated to recognize the 'strict' naming convention.
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