Connection denied by Server because of frequent connections

Here's the scenario, I have a tool that can be added to a website in order to manipulate images. We connect to the hosting servers to fetch the images, then do the processing & lastly save the images on the server again. The issue is we have to connect to the hosting server too many times to complete the image manipulation. Sometimes the hosting server would not allow us to save the new copy or deny connections. I'm looking for a solution to this. Please mention how you plan to solve this. Is it some kind of algo rhythm that decides the connection rate or something else.