Most of us use a app or special program like “photo shop” or “paint shop” to resize and clean up our pics. I have always tried to stay at 800X600 as my forum pics. This is significantly smaller resolution than what my cameras take. This is why a graphics program is nice to resize and clean up. It’s a art to get a 800x600 to look clean.
For example, I had to resize all my watch vacation pics and clean them up. You can turn your resolution down on your phone but it’s better to take them at your hi-res and resize them. It gives you much better results.
Taken on my Galaxy Note 8