Create a Wordpress form to update a custom post fields

I have a Wordpress 4.1 website that allows logged in users to publish and edit custom posts via the frontend. I need them to be able to add 5 photos to each post they publish. Workflow. Point number 4 is the feature I need. 1. They Login through the frontend (Complete) 2. They have access to a frontend "Admin" section (Complete) 3. They can add and edit custom posts (Complete) 4. Add an "Upload Pictures" button that will open a form with 5 upload fields. The upload has to have progress bars and should update the custom post after upload. I'm having a problem trying to upload images using CRED or Formidable Pro on mobile devices because the phone pictures are to large. I need a form to update a custom post field and when the user takes or selects the picture the form should automatically upload the image to Wordpress, show a progress bar and update the custom post field with the URL of the uploaded image. I only need the form to have 5 upload image fields: Field names are: wpcf-foto-1 wpcf-foto-2 wpcf-foto-3 wpcf-foto-4 wpcf-foto-5 In the post loop I'm creating a upload images button. When the user clicks that button the form will open and the user can upload their images to that post. When it finishes the user click a button to see the post.