Usually, info email will be provided in modern websites, either in contact page or on top of all pages, the issue here is spammer that can get the email (extract by regex or any other method), now, if converting the email from plain text to image like this:
E-Mail: firstname.lastname@example.org (plain)
See, it requires simply to consider image style and positioning, but it prevents spammer to extract the email. Another thing (side note) is to avoid image
alt attribute when using image because it makes no sense if you provided the email again in plain text.
Now, the question is: Is there any usability issue when using an image instead of plain text for contact email?