Because of the 800x600 restriction, and since I want to show the full screen, I had to resize my screenshots taken from higher resolution (and different ratio). I then filled the blank space left at the bottom with black the first time. And with nothing (left it white in Paint) the second time.
They would usually last one publish or two, but on the third, they disappeared from the Import folder.
I also realized the linked image's size had been decreased from 800x600 to something that looked like the actual size of it if it was to not count the Black/Blank fill I added in Paint.
This is a very annoying bug. Please fix.