How would you show the content and layout of an email with cryptographic signing?
You could sign the screenshot with a timestamp (out of my league though to get that right) from an untamperable source to show it hasn't been tampered with. Did you mean that?
Every day, generate an archive of all the email you received. Encrypt it, sign it, and generate a hash. Put all the hashes on a public page.
Write the procedure up, and have a VP attest that they ordered this done and have audited a random sample to ensure that it was done to spec. Get the attestation notarized. Repeat once a quarter or so. If the VP moves on or dies, make sure the new VP is on board immediately.
No need to have a screenshot, it's email. When a court requires you to show evidence, you bring in the VP, the notarized statement, a copy of the code, and the encrypted and unencrypted archive for that day.
I don't know if saving the email with all inline images and downloading all external images, having the mail clients to render this as it was at the time, packaging this up, etc. is easier than taking a screenshot (like E.g. Litmus does) E.g. for offers in an image.
