How to stop styling being stripped from email templates

I'm trying to include the following code in an email template: 

<img alt="VetSurgeon Jobs" src="">www.vetsurgeon.org/.../vetsurgeon-jobs.jpg" width="600" style="width: 100%; max-width: 600px; display: block; border: 0px;" border="0">

But when I save, Telligent strips out max-width. 

That is screwing up my email on retina screens. 

Anyone know how I stop it stripping max-width?