FACT
A fact is something we readily accept as true. We’re confident that we could somehow verify it if we wanted to.

This photograph was taken by Virgile Lafreniere using a Canon Rebel EOS 300D, 18-55 Canon II EF-S f/3.5-5.5, Kingston CF 2GB 100x.

INFORMED OPINION
These refer to things we didn’t know before but we don’t bother to question them because the other person seems to know more about the subject than you do. Besides, you’re not really that interested.

“I notice some noise in the northern lights that look more like JPG artifacts rather than camera noise. Reprocessing with less compression might make it go away.”

“A difficult photo as there are different lights – the one coming out of the igloo and the auroras. The result is clear details, soft colours and no noise despite highish ISO.”

PERSONAL OPINION
These are things that can’t be verified because they are subjective. They might be true for the person who thought about them, but you might not think so yourself.   

“The igloo, isolated in its inhospitable landscape says something of man’s tenacious existence on the planet.”

“The horizontal line of the igloo entrance and the lowest part of the aurora borealis are mirrored about the horizon, alluding to how our planet mediates between us and The Universe.”

“The aurora arcs down to greet the igloo whose yellow glow extends and completes the aurora’s spectrum of reds, blues and greens.”

“The only three sources of light are the igloo, the aurora and the stars, suggesting a unity between man, the sky and the cosmos.”

(It’s worth remembering that all these thoughts were suggested by the presence of this igloo yet the person who built the igloo intended none of them! All they did was build a simple shelter using what they had.)

But this is fine – after all,

“Beauty is no quality in things themselves – it exists merely in the mind that contemplates them.”
                David Hume

If something sounds true yet you feel uneasy about it, then Personal Opinion is probably being presented as Informed Opinion. This happens a lot, especially with matters of aesthetics.