I don't entirely agree.

In fact - the channel numbers are not so much of an issue. The first time my application is used, it downloads the "subscription" page, where you can select which channels (by name) that you want the tv guide to display (i.e. exactly the same thing you do on the real tv guide website).

It then stores these names, and each time you use the app after that, it downloads these channels. The tv guide site stores the channel numbers for each channel - so my app doesn't "know" the numbers for each channel - but it does use the numbers the site provides. The channel names are listed on the left, and when you press the channel button, it will change channel. The tv guide site does not always have the numbers correct for all channels, so manual entry of a channel number is possible when selecting which channels are subscribed to.

In addition, the tv guide site also provides summary info for each program - my app stores that too, and pressing on a program title will show that summary.

Searching for tv progs is also possible - again, it's a function the site itself provides so my app provides the same.

Although you could perhaps just download a screenshot, you'd need several if you wanted to display more than a few channels. My app shows 2 hours worth of programmes for 8 channels per page - and typically I subscribe to enough channels to fill 10 pages. And of course, if you wanted all of the functionality I've mentioned, that wouldn't be possible with screenshots. The app needs to be quite site specific to allow that kind of functionality.