I have installed PWA venia in frontend magento 2.3 but images are not loading.
I faced the same problem and was able to resolve it by creating Virtual Host (the reason why it is necessary, is to resolve the CORS erros).
You can view CORS errors when opening the 404 image in a new tab, you will get erros in console.
Create virtual host by following all steps mentioned here. Point Virtual Host to pub directory of Magento instance.
Give that VH URL in env file as well. This link may be very help full as well.
First create a virtual host for your magento root directory. If you are dont know how to setup virtual host please follow the link : https://www.digitalocean.com/community/tutorials/how-to-set-up-apache-virtual-hosts-on-ubuntu-14-04-lts
Next you need to edit the file named "makeMediaPath.js" which is placed in the path
Now change the following line
const mediaPath = 'http://magento23.com/pub/media/catalog';
In the above line please replace "magento23.com" with your virtual host