Thank you Sakin!
I decided to just make the images in the posts 500px and then with the option to click on them for a bigger version. Then the images will stay relatively small in size but big enough to see what’s actually on the pictures.
With the width you mention it doesn’t seem like I will have any problems with images being too big.
The site is not public yet so it only shows “Under Construction”.
I will look into jpegmini you mention.
Thank you for your time and help!