Think of your email signature as a quiet marketing space that never takes a day off. By keeping your call-to-action up to date, you can turn everyday communication into an effortless touchpoint for bookings, promotions, or content.
Our dynamic Call to Action (CTA) feature lets you:
Swap campaign banners instantly (think “Spring Offer”, “EOFY Sale”, “Book Now”)
Update links across your team’s signatures with a single click
Keep every outgoing email aligned with your latest campaign or promotion
No plugins. No endless reinstalling. Just smooth, centralised updates.
Open your signature
Go to your dashboard and open the signature you want to edit..
Click “Update” Next to the CTA Image
Next to each CTA image, you’ll see an Update button. Click it.
Upload your new image
Upload your replacement banner and click Replace.
⚠️ Important: Your new image should be the same dimensions as the existing one. Using different dimensions will cause stretching.
If you need a new size or format, we recommend removing the old image, uploading the new one, and asking users to reinstall their signatures.
Wait for it to update
Email clients cache images to improve load times, so please allow up to 24 hours for updates to appear everywhere.
You can dynamically update where users are directed when they click your CTA banner — no reinstall needed.
In your signature editor, update the Call to Action Link field.
Click Share → Update Share Link to publish the change.
🚨 Crucial step: If you don’t publish your changes, users will continue sending the old link.
That’s it. All live signatures linked to that share will now open the new URL.
My CTA link didn’t update.
You likely forgot to click Share → Update Share Link. Publish the change and it will take effect immediately.
My new CTA image isn’t showing up.
It’s probably cached. Webmail usually refreshes within hours, but desktop Outlook can require a reinstall.
My replacement image looks stretched.
Ensure your new image matches the original width and height exactly.
Seasonal campaigns: swap banners to reflect offers like Summer Sale or EOFY Deal.
Event promotions: link to registration pages or booking calendars.
Content marketing: rotate CTAs for new blog posts, videos, or case studies.
A/B testing: try different messaging (e.g. Book a Call vs Get a Quote) and measure which gets more engagement.
Dynamic CTAs behave differently depending on how each email client handles images in your signature.
Your CTA link updates instantly everywhere — as soon as you click Share → Update Share Link, every client will open the new destination.
The only difference between email programs is how quickly they refresh the image itself.
Here’s what you can expect across the most common platforms:
If most of your team or customers use Gmail or Outlook.com, you’re in luck.
These web-based clients load your signature images directly from the web each time an email is viewed, so when you replace your CTA image on Signature Hound, it updates automatically.
Gmail has handled images through a secure proxy since 2013, meaning images refresh automatically after a short cache delay.
Outlook.com (Microsoft’s webmail) works the same way — images are hosted remotely and refreshed when viewed.
In short: webmail clients fetch the latest version of your CTA banner automatically.
Apple’s Mail apps (on macOS and iOS) use Mail Privacy Protection to keep user data private.
That means Apple’s servers download and cache all images before you even open the email — including your CTA banner.
Apple describes this process in Mail Privacy Protection.
On Apple Mail, your CTA image will update, but unlike webmail clients it may take some time because Apple loads the image via its cache/proxy system. Some testing suggests updates may appear within a day or two, depending on how the user’s device and mail-app handle the caching.
In short: your CTA image will update, but it may take a couple of days for Apple Mail users to see it.
Desktop email apps like Outlook Classic for Windows save your entire signature (and its images) locally on the computer.
Once installed, these apps don’t check for image updates online — so if you replace your CTA banner, users won’t see the new one until they reinstall their signature.
Microsoft confirms that Outlook desktop stores signatures in local folders, not online.
In short: image updates won’t appear automatically. Reinstallation is needed.
(Link updates, however, do work instantly once you click Share → Update Share Link.)
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