As I understand, the majority of flat earthers say that images from Hubble are fake. Although this may not be a universal belief.
However, cast your minds back to 1990 when the first images were released. They were only slightly better than what the best telescopes on the ground produced and very far short of the promises of unprecedented views of the universe and all the opportunities for new discoveries and insight.
The reason was (allegedly) that the primary mirror had been ground very slightly out of shape. The reason given for that was someone had put a washer where it shouldn’t have been on a piece of test equipment to verify the mirror’s shape.
In short, it seemed a total bust.
That was a major embarrassment for NASA and the companies that (allegedly) built it. As always, many people were questioning NASA’s budget and this did not help at all. Bare in mind at the time, there was no ISS, climate and earth monitoring wasn’t really on the general public’s radar, and no one was seriously talking about manned missions outside low earth orbit.
Hubble was the most expensive non military satellite ever built (allegedly), and had been presented to the public as game changing.
It took 3.5 years to (allegedly) devise and implement a fix for the optics error and for Hubble to start producing the quality of images (and other data) we were originally promised.
So if Hubble is fake and all the images are fake, why would NASA damage their reputation by inventing a fake optical problem?
PS. This isn’t the only embarrassing mistake by NASA. I particularly remember the Mars Climate Orbiter disintegrated in the atmosphere because a piece of software incorrectly outputted data in the wrong units screwing up the trajectory.