Make Image Clickable Phone Number

Hello

We have an image that reads "Call us at 888.321.1212" and we want to make it so when someone clicks on the image from their mobile device it will dial the number. I tried to add <a href="tel:888.321.1212"> prior to the code to insert the image <img src="image.gif" alt="Get Holiday Coverage. Call us today at 888.321.1212 to discuss you holiday staffing needs" width="600" border="0" style="display:block">, but that didn't work.

Here's the code in its entirety:

<a href="tel:888.321.1212"><img src="callus.gif" alt="Get Holiday Coverage. Call us today at 888.321.1212 to discuss you holiday staffing needs" width="600" border="0" style="display:block"></a>

This did make the image clickable, but it open up a web browser for the marketo token and then goes to the phone, but has the wrong number. It shows the phone number, but has a bunch of other numbers after it: 8883211212355728269335781447488286.

Any idea what I'm doing wrong??

Thanks!

JD