Default settings
Click the Image button in the rich text editor, and choose the image you want in the Edit Image window. Click save, and it will be added to the page.
Wider than the text block
In the Edit Image window that allows you to add an image, scroll down to the Enhancement Styles area, and change the Enhancement Image Size to Medium Promo.
The full width of the window
In the Edit Image window that allows you to add an image, scroll down to the Enhancement Styles area, and change the Enhancement Image Size to Full Width.
Card Image Only Grid
Add a Module to the article and choose List in the first dropdown as the Module type. Populate the Items in the list with images or promos that have images. In the List Styles section, change the Template to Card, Image Only. Change the Column Count to the appropriate number for the images you want to display. Scroll to the bottom and toggle on the Full Width Grid Form switch.
This module will always show the images in a square aspect ratio. It allows for three or four columns.
Vertical, Centered
In the Edit Image window that allows you to add an image, scroll down to the Enhancement Styles area, and change the Enhancement Image Size to Vertical.
Pulled Left or Right
Add an image to the article. In the Enhancement Styles area, set Enhancement Alignment to Left Aligned or Right Aligned.
The image will keep its original aspect ratio, but will float to the left or right of the text that follows it. Make sure there is enough text following it to push other content down, or you could get weird results in the layout, like headings or other modules getting pushed over to the side of the image.
Carousel Grid
Add a gallery to the article, and in the Carousel Styles section, change the Template dropdown to Carousel Grid.
This will lay out the images in a grid format, but it will align the tops of each row of images. So if the images have different aspect ratios, it could leave white spaces in some rows, especially if there are horizontal and vertical images next to each other.
Carousel Default
Add a gallery to the article. In the Carousel Styles section, leave the template at Automatic or set it to Carousel (Default).