So I'm pretty sure your friends were exaggerating, or meant hi-def in a different sense.
"Our discovery, or rediscovery, that around 2-3% of the population, with aphantasia, lack a mind’s eye, and that a somewhat larger percentage, with hyperphantasia, have imagery that is ‘as vivid as real seeing’ has captured huge public interest, and led to a sustained surge of citizen science. We have been astonished – and delighted – to receive over 14,000 contacts from members of the public with extreme imagery since coining the terms in 2015."[1]
> ‘as vivid as real seeing’
I can only take others' word for it, but why would I disbelieve this? Especially when I myself have the other extreme of nothingness? Why would so many people lie or exaggerate about seeing mental imagery "as vivid as real seeing"?
[1] https://sites.exeter.ac.uk/eyesmind/2020/05/04/an-update-on-...
I take you at your word for your experience. I likewise have no reason to think my wife, for example, is exaggerating to me. My wife has a photographic memory, and she can literally recreate stuff down to almost absurd details. I think it is possible you may be underestimating what other people see in their minds. :)