Hi,
I'm an expert java developer, I have worked on many java enterprise projects. I can help you with the task here.
This is easy task, will take hardly 2 hrs to complete if you assign it to me.
The way i'll proceed is to make the image as Graphics2D and then add a mouselistner. After that whatever operation you want can be done.
Once the operations are performed, we can download the image using htm5 download option.
Please initiate a chat to confirm.
Cheers,
Akash