Customize file upload script for IScipts Multicart 2.4

I am creating a multi vendor ecom website using the Iscripts Multicart 2.4 Script. I need to modify the image file upload script as it curently only allows one image to be uploaded at a time, and requires a separate small gallery image and main image. I would like multiple images to be able to be uploaded in one single step using the free Jquery File Upload plugin code found at [login to view URL] The image upload section for products will change as below a. Option for upload 'Small image' (while adding a product) will remove b. Option for upload 'Big image' (while adding a product) will remove. c. Seller will be able to upload all images in a single step. d. At least one image will be required to add a product. e. A maximum of 5 images will be possible to upload with each product. f. Maximum file size of one file will be 700kb and preferred resolution will be 1024x768 g. The thumbnails and the small image will be created automatically from the main images. h. Seller will be able to select one of these images as main image. Later he will be able to change this to any of the others. i. The current method for uploading multiple images will change, instead this will replace with the jquery upload similar to that of [login to view URL]> [login to view URL] j. Aspect ratio must be kept the same for uploaded files. Assumptions and Limitations: 1) 'Display More Product Images' option will hide from the admin panel>>general settings. 2) 'Product More Image Limit' option will remove from admin panel>>general settings. 3) Image upload section for product will change in seller and admin panel. No option to upload a big/small image, instead this will have an option to upload multiple images simultaneously. Also there will be option to select one of these as the main image. 4) Product more images limit will set to 5 by default and will not be changeable.