Icons for actions

For three Emails, I like to add icons.

First Email: User has to confirm his email address (see https://litmus.com/checklist/emails/public/3a1c0d4) Second Email: User has to respond via email to the registration email (see: https://litmus.com/checklist/emails/public/ec4f2e4) Third Email (see: https://litmus.com/checklist/emails/public/b267f74)

Image sizes like in the example references for retina displays and responsive purposes 150x150 px