I seem to have no problems opening them in Safari, or Preview ... If you want to download them rather than viewing them in a browser, you can right-click (or Control-click) the issue's cover, then select "Download Linked File As", and pick a name and location to save. Then just open it with Preview (or Adobe, if you prefer).
How can you get the CoH comics on a mac? When I try to get them, it just say that it can't open the page.. ?