I save the images on my computer, marked in order and labeled to make it easier to retrieve. The images should be 500 KB or so and less than 1000X1000.
It is better to post a few images to demonstrate what you want to show, then start another post in Reply with the next series, and so on.
It is important that each image is where you want it to appear, with the caption.
Do that by typing your text, then skip a space and the image code string will appear where your cursor is located when uploaded.
After typing the text, click on 'upload image' at the bottom and this will appear
Click on 'browse from your computer' and find the image, the click on it, and this will appear with a thumbnail of the image
Click on 'Upload" and the code will appear where your cursor is.
Then skip a space, type your next text, skip a space, and upload the next image.
BE SURE AND CLICK ON PREVIEW because you cannot edit the post after clicking on 'Post'