This is a core block and thus available by default in Gutenberg WordPress editor. No download required.
WordPress Image Block in Gutenberg is the most common media block. It allows you to display an image anywhere on the page or post. Besides the paragraph block, this should be the other most needed block in Gutenberg.
Image Block Features
Image block has alignment options in the block toolbar. To resize the image you get draggable resize handles on the image to simply drag and resize your images. From the sidebar settings, you can write the Alt text, select image size and also adjust the dimensions using the options here. You can also adjust the link settings here.
This is how an image display on frontend using the image block in Gutenberg.
Image block added on a page.
You can resize an image in the image block by dragging the resize handles simply.
These are the settings available for the image block in sidebar.