adding upload jpeg button to form

Site URL: http://www.siouxpremetattoo.com

Hi, I was hoping someone might have the magical code i need to add an upload button to my form? I'm in desperate need of one as it really helps cut time down for the consultation process when customers can upload image references.

Please help.

Also... do you know if the code changes with the template as I'll need to do this for another website that isn't live later today/tomorrow??