The iPhone (and iPad) shoot large jpgs, and HEIC files are compressed more than jpgs, so it doesn't surprise me that converting the latter to the from means an increased file size.
In the 'Phone's Settings, change the format to Most Compatible and it'll be jpg.
Pictures should than be saved as jpgs.
Check the file size and quality against HEIC pics.
Check the file size and quality of HEIC pics converted to jpeg.
If their the same, great.
Then see if you can reduce the size of the converted jpgs down to bite size.
You can avoid all this by saving pics as jpgs in the first place.
But then you defeat the advantage of HEIC.
I think most or at least some of the above is correct.








I am that Masked Man.
All you can do, is all you can do.
There’s trouble — it's time to play the sound of my people.
Your boos mean nothing to me, I've seen what you cheer for.
Insisting on your rights without acknowledging your responsibilities isn’t freedom, it’s adolescence.
I've been to the edge of the map, and there be monsters.
We are a government of laws, not men.
Everybody counts or nobody counts.
When a good man is hurt,
all who would be called good
must suffer with him.
You and I have memories longer than the road that stretches out ahead.
There is no safety for honest men except
by believing all possible evil of evil men.
We don’t do focus groups. They just ensure that you don’t offend anyone, and produce bland inoffensive products. —Sir Jonathan Ive
An armed society is a polite society.
And hope is a lousy defense.
You make me pull, I'll put you down.
I *love* SIGs. It's Glocks I hate.