I see! I have tried to manually adjust such, but it is trial and error. And as about every third word I type is a typo due to stiff arthritic typo-fingers, is there a site that adjust images for you?
<img width=400 src="">
And then I just copy/paste the web address of the image between the quotes. Almost always, a width of 400 is fine. Every now and then I stretch it out if the graphic is short and wide (like if I'm posting one of the climate change graphs from https://energyeducation.ca/wiki/images/8/8f/Ice_ages2.gif).