How to Add an Email Signature in Mimestream (the Mac Gmail App)
Mimestream is the native Mac Gmail client a lot of us switched to — fast, Mac-assed, built by an ex-Apple Mail engineer. It has its own per-account signatures, and here's how to set up a designed one (with a photo or logo that actually renders) instead of a plain-text footer.
Mimestream uses Gmail's accounts but keeps signatures in its own settings, per account. It supports formatted signatures, so you can have a real designed signature — you just need clean, email-safe HTML with hosted images, which is the part people get stuck on.
Step by step
Open Mimestream's signature settings
In the menu bar: Mimestream → Settings → Signatures (or ⌘ , → Signatures). Signatures are set per account.
Choose the account
Pick which Gmail account this signature belongs to. Mimestream lets each account have its own, and set a default for new mail versus replies.
Decide: plain text or designed
For a simple text signature, just type it here. For a designed one — photo, logo, brand colors, social icons — you need HTML with hosted images; keep reading.
Build the signature with hosted images
The images must be hosted web images (https URLs), not pasted image data, or they'll break for recipients (why). Design it in Autograph, which hosts and bakes the images email-safe.
Copy it as HTML
In Autograph, use Copy HTML (or Copy signature) — it puts the designed signature on your clipboard as rich HTML, ready to paste.
Paste into Mimestream's signature editor
Click into the signature body in Mimestream's Signatures settings and paste. The formatting, colors, and hosted images come across intact.
Send yourself a test
Compose a new message in Mimestream, confirm the signature appears, and check a test email in Gmail and (if you can) Outlook — images crisp, links working.
Design once, use it in Mimestream
Build a designed signature in Autograph with hosted, email-safe images, hit Copy HTML, and paste it into Mimestream. Or install it one-click into Apple Mail — your call.
Download Autograph free See the templatesCommon questions
Does Mimestream support HTML signatures?
Yes — Mimestream supports formatted, per-account signatures. You can paste a designed HTML signature into its Signatures settings, as long as the images are hosted web images rather than pasted data.
Why do images break in my Mimestream signature?
Because they were pasted as image data rather than referenced as hosted https URLs. Use a signature whose images are hosted (Autograph does this automatically), and they'll render for your recipients.
Can Autograph install directly into Mimestream like it does Apple Mail?
Not directly — Autograph's one-click install targets Apple Mail's signature store. For Mimestream, use Autograph's Copy-HTML export and paste it into Mimestream's Signatures settings; the design and hosted images carry over.