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-- Google Gmail Advertising
---- Gmail blows up e-mail marketing by caching all images on their servers
phranque - 12:51 pm on Dec 13, 2013 (gmt 0)Thread source:: http://www.webmasterworld.com/gmail_advertising/4630311.htm
it's not clear from the post whether gmail's proxy image server will respect any cache-related HTTP Response headers, such as Cache-Control and Vary.
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