Need someone who can code on WIX, looking for custom image upload and cropping function

I am looking for a Javascript coder that can develop a functional widget using WIX’s “Corbid” develop tool now known as Velo as of 2 weeks ago when they re-branded. It is important that they know how to code my existing Point of Sales software coding, into the functional application I am needing to be designed so it is all one streamlined buying experience for customers who shop in our physical store and purchase online

I need there to be a minimum size requirements for photos being uploaded as well.

In a perfect world I would like the code to function like Metalprints.com, see link below

https://www.metalprints.com/ordering/product/single_metalprint

Here is a secondary website that I would settle for if budget doesnt allow for our first option.
https://www.artbeatstudios.com/order

Our Point of Sales system is powered by Shopkeep. SHopkeep produces code that allows you to plug it into an eCommerce platform so that inventory and sales figures are synched up with in-store purchases as well. I would need this code to be integrated into the checkout process.

Important requirements
– Must be able to upload files as large as 100mb
– Must be able deny uploading too small of files
– must be able to choose a crop of the uploaded image if choosing a smaller size
– Must be able to synch POS software into checkout process