What is the best way to provide files for download from an AWS EC2 instance? [duplicate]

So I am supposed to create an application that uploads files(images) to an AWS Ec2 instance running Linux. I used Flask to create the upload logic and a simple HTML webpage to upload files.

After this I am supposed to generate a thumbnails and web optimized images from these images and store them on a directory and then provide the "web-optimized" image directory for download. How do I achieve this?

I have asked this previously here. I have pasted the code that I am using on that thread as well.

So my questions are :

1. Is it a good idea to use pscp to transfer files to the EC2 instance?

2. Is it a good idea to use paramiko to run a ssh on the remote instance in order to invoke a shell script that does the image processing (thumbnail web-optimized image generation using python)?

3. How do I get the compressed images via a simple download button on the client/host computer?

Thanks.