To begin with, the OP's first sentence written in direct speech is incorrect. The pronoun and the auxiliary verb is never contracted (I'm, I've, you're, he's, she'll, we'd etc. ) at the end of a positive sentence.
She asked, “Are you well?”
Yes, I'm. (NO) “Yes, I am.” (YES)
“Will he stay?” she inquired.
Yes, he'll. (NO) “Yes, he will.” (YES)
He said, “...
The reason we use the present tense to describe a person in a photo or a video, is similar to the reason that we use the present tense when we are discussing or criticizing the actions in a novel or a play, but sometimes the past continuous is correct as in the example that follows.
For example, in discussing the play Hamlet we would generally use the ...
It's a narrative trick. The speaker is trying to engage the listener, probably emotionally, and using the present tense can make the story seem more immediate and relevant.
"He is wearing a hat" induces further questions, like 'Why? Where did he get it? Does he wear it a lot?' The past tense makes such details seem distant and unimportant.
It's a ...
You can use the past tense, if you are talking about what the person who was photographed was doing.
But normally, when you look at a picture you describe the things in the picture in the present tense. The picture doesn't change, it's always the same.
It's the same type of thing as describing what's depicted in a painting. Especially if the painting doesn'...
When describing what is present in the picture we tend to use present tense:
That is granddad. He is wearing a hat.
The continuous form is used, although it might not be "logical", at any rate we treat the picture as if it were happening now. It's not required, and if you use a past time you'd also use past tense
That was granddad in 1951. He was ...
In example 1, the choice of "this is" or "this was" has less to do with when you found it, and more to do with when you're showing it or talking about it.
Either is fine, but probably you want to say "this is" if you're introducing this fact: "This is what I found: 4 new data points". You'd probably use the past tense if the information is no longer fresh ...
A few points:
You could use this: "even less than half that of the reading". I'd also consider ending the sentence there and start the next with Subsequently.
I am fine with "has been becoming" - sounds good to my ear.
doesn't quite work. Consider "more trivialized" as it actually flows well with your statement.
In your ...
This is an example of reported speech that has not been backshifted.
It is common and correct to "backshift" when changing from direct quote to reported speech.
My friend asked me, "How are you?" (direct quote)
My friend asked me how I was. (correct and backshifted)
But while it is common, it is not a requirement for correct grammar:
My friend ...
Your example is fine. You watched (past tense) the movie because that event happened yesterday, but the movie talks (present tense) because the movie, as a recording, will continue to talk to others.
This is often the idiomatic way to refer to recorded media, including the printed word. Just consider these quotes from book and record reviews:
"... the ...