Better still - don't post images unless they are essential. Consider posting a thumbnail with a link to a larger image. This doesn't apply to social interaction threads of course.
Even more important - please don't quote an image - we've seen it once, and that should be enough.
Good suggestions, all of them. There were a few members who were making it a habit to post extremely large, unnecessary images when they created threads, much like mainstream media sites do--images that add nothing to the post and contain nothing useful. I was so annoyed by this that I created
a thread about it late last year. Some of the members stopped posting those images as far as I know, for which I'm grateful.
And yeah, when someone replies to a post and quotes an enormous image, it drives me nuts--or even when they quote huge blocks of text just to make a short post.
I recently started a thread about my experience with using a bitcoin ATM and included images. Initially they were huge, but I got advice from o_e_l_e_o about resizing them:
Edit: Change your [img] tag to [img width=500] (or a different number) to resize your massive images.
Not being very proficient in coding, I wouldn't have figured out how to do that without a little help and some constructive criticism from a helpful member.
. You can't feel it actually. However, there's one thing which made me convinced on using image compression — the faster data transfer. My device is low tech and sometimes it's having a hard time to load the webpage especially when there are so many images on the thread I visit. That's why I think it would be advantageous for me. 
