Directus hosts images through it's media library. This can be locally on the server or an external provider. Rather than link to the images directly, you can use Directus to deliver images to your application with ease and security. Best of all, you can optimize images for web using the built in parameters.
The URL for images in Directus is https://<project-host>/assets/<image-id>. Then add any parameters to the end starting with a question mark (?) then seperate each parameter with an ampersand (&).
Directus has great documentation on how you can deliver images. Be sure to read them over.
Here is an example: