This details how to convert PDF pages to JPG or other image files from the Linux command line with relative ease. A much viable option for those comfortable with the Linux command line to avoid having to upload to the numerous online converters available, keeping it local to your own system.
I use a lot of different cloud providers and I just wanted to throw out there for those not familiar with Vultr.com, they got a promotion going on for new signups, get $50 in credit to try out their solutions.
The one thing that makes Vultr.com stand out from some of the others is they provide smaller instances that start at $2.50 a month for IPV6 only connections but also have $3.50 a month instances that include IPV4 connections.
These smaller VM's are great ways to do testing, rolling out clustered VMs, etc.
If you're looking for a cheaper solution for cloud infrastructure, these people have been great.