We're doing some housekeeping of the ideas forum here and this post popped on my radar. As mentioned above, this functionality is currently supported in the HubSpot CRM. I'm going to move this to the status of "delivered". As always, thank you for your continued input on our product.
This is currently in beta! Once ungated for the new functionality, we will not drop email attachments and images from emails that are logged in the CRM. We are planning to roll this out fairly slowly to make sure everything is performant, so if you would like to be a part of the beta, please fill in this form and I'll ungate you: https://goo.gl/forms/E5ArmzGTA5EGhpXk2.