The image component is exactly what it says it is - a way to add a resizable image to a campaign.
As with other components, you can easily configure the size using the transformation controls or the dimensions, as well as add a background fill or border. One additional and important property you'll need to configure is alt text.
Alternative text serves several functions:
It is read by screen readers in place of images allowing the content and function of the image to be accessible to those with visual or certain cognitive disabilities,
It is displayed in place of the image in browsers if the image file is not loaded or when the user has chosen not to view images,
It provides a semantic meaning and description to images which can be read by search engines or be used to later determine the content of the image from page context alone.
Once all you're happy with the size and have created an alt text, your image component is ready to go.
NB Saving a campaign that includes images without alt text will provide you with a prompt to include one as it is an important property for accessibility purposes, something that is legally required under ADA regulations for US users.