InfoPath Dev

I have a form where the users have to attach a copy of their drivers licence and the users havent been putting the file in the correct format before submitting so we cant always open the licence. Is there a way I can only allow the users to attach a file that is either .jpg or .pdf?

Is this in the browser or in filler? In filler, in the control properties, you can create a restriction. In the browser, you'd need to use code or qRules to get the file extension of the attachment and then you could remove the file if it is in the wrong format, or display an error, or whatever you'd like for your UI.