Receiving Memory Error with Flask when auto-generating images

Exception happened during processing of request from ('127.0.0.1', 40366)
Traceback (most recent call last):
File "/usr/lib/python3.5/socketserver.py", line 625, in process_request_thread
File "/usr/lib/python3.5/socketserver.py", line 354, in finish_request
File "/usr/lib/python3.5/socketserver.py", line 679, in __init__
File "/usr/lib/python3.5/socketserver.py", line 731, in setup
File "/usr/local/lib/python3.5/dist-packages/gevent/_socket3.py", line 229, in makefile
MemoryError

I've been receiving a memory error (after a while of working) from Flask, which I use to autogenerate images and host a website. The problem is that my hosting has 2gb of ram and it ram usage doesn't go over 30% that much. Here's the graph:

Here's a copy of my code: main.py Acnl.py

What could be causing the issue? I'm not aware of what it could be. Restarting the upstart process works but it's only temporary.

Edit: I'll like to point out that I do know what a memory error is but don't understand where it's coming from. Like, which part of the code is causing it.

Solution

What I did was host the images rather than get it from url with requests that helped a lot!