There are two distinct use cases to get URL of an image:
In most cases you should use CDN, because the images are cached and provided with lower latency.
We have extended endpoint Eshop Info, section imageCuts to contain cdnURL to provide a CDN path for each particular image cut.
Additionally we added cdnName to all endpoints providing images, such as Product detail, Product list or Order detail. The cdnName contains a timestamp encoded, which get changed whenever the images changes (e. g. a new version is uploaded). The full image URL can be easily built by concatenating cdnUrl and cdnName.
See also a separate article Product images.