Gmail webmail displays an image download icon when a user moves their cursor over an unlinked image.
Gmail HTML codes
A list of all CSS properties supported in Gmail and Inbox.
If your email exceeds 102KB in file size, Gmail will display the first 102KB along with the the message “[Message clipped] View entire message”.
The desktop and mobile version(s) of Gmail automatically convert phone numbers and email addresses to links.
Gmail and Yahoo! Mail add a spacing between images. This issue first showed up when viewing emails in Firefox and later spread across other modern browsers including IE, Chrome, Opera, and Safari.