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"Gmail serves all images through Google’s image proxy servers"
Ao usar o Outlook para acessar uma conta do Gmail, as imagens serão extraídas dos servidores proxy de imagem do Google ou dos servidores originais?
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How Gmail makes images safe Some senders try to use externally linked images in harmful ways, but Gmail takes action to ensure that images are loaded safely. Gmail serves all images through Google’s image proxy servers and transcodes them before delivery to protect you in the following ways:
Senders can’t use image loading to get information like your IP address or location. Senders can’t set or read cookies in your browser. Gmail checks your images for known viruses or malware. In some cases, senders may be able to know whether an individual has opened a message with unique image links. As always, Gmail scans every message for suspicious content and if Gmail considers a sender or message potentially suspicious, images won’t be displayed and you’ll be asked whether you want to see the images.
Acho que você respondeu sua própria pergunta
"Gmail serves all images through Google’s image proxy servers"