Based upon the fact the returned 404 page appears to be the default Apache 404 page and not Zen Cart's 404 page, it appears you may have placed the CEON generated ".htaccess" code into the wrong ".htaccess" file. If the ".htacess" file was in the root Zen Cart installation folder most requests (including for the URI you posted) would be sent to Zen Cart and Zen Cart's 404 page would be displayed.
The top of that ".htaccess" file looks like the one in the "images" sub folder. If you accidentally merged the contents with the ".htaccess" file in the "images" sub folder you will want to undo the changes.
Are you sure you added the rules to the ".htaccess" file in the root Zen Cart installation folder?
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