Craft stores all of the files you upload as Assets, which can be found in the Assets tab in the Control Panel. Assets are organised into folders based on how they are used on your site such as Files and Images. You can view the files within a folder by clicking on it in the sidebar.
There are two different layouts; list or thumbnails. You can switch between them using the icons in the top right.
As with Entries, you can sort, search and filter your assets using the toolbar at the top.
Adding alt text to your images is important for several reasons. For blind users navigating your site with a screen reader, the alt text will be read out to them to describe the image. It's also important for search engines, as alt text will help tell what kind of content is on the page. To edit the Alternative Text, click on the asset's blue title and you'll be taken to the edit page, which works exactly like Entries. Alternative Text will be an editable field for the asset.
Craft also has an image editor built in which lets you do some basic image manipulation without the use of something like Photoshop. Either of these methods will work:
Click the checkbox next to the asset, then the cog wheel at the bottom, then Edit Image
Or, from the asset’s edit page, hover over the image thumbnail and click Edit Image
This will give you an interface similar to the screen below where you can rotate, crop and flip the image.
Craft’s built-in image editor
When an image is shown on the front end of the website, we always crop / resize it to make sure it works well with the design and so you don't have to think about resizing images first. Large images make pages load slowly, so we resize them appropriately in code first before your customers view the page.