As long as your artwork is on the Internet, there is very little you can do to protect it from downloading or theft. No matter what kinds of tricks that web developers employ such as disabling the right click, it's very simple to circumvent or just take a screenshot.

ArtStation downsamples and resizes images that are uploaded if they are larger than a certain size to make it web friendly.

When a user browses ArtStation, we serve the web friendly version of the file to the user to view. ArtStation is a responsive website and we resize the image in CSS to fit in the viewport, we provide an expand button that links to the same file, in a new window. We also provide a download button that links to the same file, but sends it to the user so that they can download it easily for collecting references.

When viewing a project on ArtStation, the download button simply links to the same image that is already being served to the web browser to display on your monitor - i.e. you actually already have the image on your hard disk by just loading it.

We repeat - the download button delivers the same file that is already being sent by our servers to the user's web browser to view on the website - disabling the download button is a frivolous feature and does absolutely nothing to protect your artwork because the user already has a copy of it on their hard disk by viewing it on their web browser.

But other sites disable right click and don't allow downloads

This is completely useless. It is a placebo feature to make you think that the platform is securing your artwork. A user can open the browser developer tools and retrieve the file that was sent to the user. A user can also just take a screenshot. There is no such thing as copy protection if an image shows on a user's monitor.

If you are seriously concerned about your work being stolen, we recommend that you don't upload it to any publicly facing website.