Add file upload to an html form

We need a file uploaded to the html form that is on [[login to view URL]][1] This should fit in with the rest of the form on the website, work with the installed captcha and email the uploaded file as an attachement to the email address installed on the form. This file upload would preferably only allow all/most images types not other document types ie .doc etc. The worker we select will be given access to a clone of the website, once the work is done we will be transferring it to the main site so a list of the files you have edited to achieve this will need to be provided to us along with info of what was modified, this is to prevent any down time on the current live website.