Well, judging from the error message, what that usually means is that the pictures on the page aren't encrypted, which is fairly common as it saves on server resources and bandwidth.
It's probably chrome being over-cautious.
I've not tested it in chrome myself because I don't really like it that much, so maybe someone else will come along and tell you if they have the same issue.
Also, I imagine that clicking the "What do these mean?" button may provide you with similar info...
Note (slightly unrelated):
On a personal note, I hate applications that give vague error/warning messages.. "There is some problem somewhere" doesn't help you fix the problem or know if it's safe to continue anyway... So if anyone develops any apps, please have helpful error messages. (As a developer it's a 'pet peeve' of mine)