Sorry, sorry… I completely forgot to post how I resolved the issue.
After trying most of the solutions on other posts, I considered another possibility. I contacted my hosting service provider directly, and so it happened that that way that my hosting service manages MySQL (I phrase it this way because I am not a pro on this so I have no idea if other services manage differently) required an extra setup to be done to allow for the GD gallery to create the thumbnails. Once they had set that up for me, I was up and running in no time.
