Generate Multivariant Child in Virtuemart automatically with images

VMVendor ([login to view URL]) Vendor Owners can make products in Virtuemart from one uploaded Image png file in specific size 2400 x 4800 px. Product will be generate like child in Multivariant in Virtuemart. We have now finished product designer (something like tshirt designer) which can generate preview of design with combination of Product Design + Uploded Image by user. We need use part of this designer to generate product images for Multivariant (Virtuemart). This will be very important part - generate main product images for child in Virtuemart, each child will have own image (merge product image + design by vendor owner). Full specification in attachment. No milestone before finish project.