Hi, I have 4 years of experience with python. I am currently working on two other twitter based projects.
As I understand, you need to find followers of the account, send messages to new followers, upload files to the account and send tweets periodically. You want to be able to do this for multiple accounts. For these purposes, twitter provides its api. You would have to get api keys for every account that you want to manage. I will use tweepy module in python for using the twitter api. If you want to run the scripts on your computer you will have to install python and tweepy. Depending on other constraints like user interface, this project may take up to 15-20 days.
I will provide readable and easy to use scripts. I will also provide full documentation and appropriate comments in the scripts. I will also provide a README for the project, which will document how to use the scripts. I will also explain to you what the scripts actually do, if you need to understand how they work. You can expect daily updates on the progress of the project.
Please contact me before awarding the project, so that we can discuss the details of the project.