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I will take a look at it but it's not the issue that SEOMoz tell me as this format concerns only images. It's actually a little trick to do lazyloading on images. The link you pointed out on your example is good ("/annuaire,amkashop,site,promotion...) as comma are not encoded. And for your example I see no issue except capitalization. I bet this is a Moz problem because when I fetch as Googlebot, I don't find encoded URL...