iOS / xCode4: image sizes for TableViews and Pickers

Is there any indicator in xcode about the size of table cells and picker cells, so I can work out how big my images need to be 开发者_如何学Goin there, how much gap to leave for the edges etc. Just need some kind of guidelines indicator as to where my cursor is on the control I suppose. How do you guys deal with working out layouts?

Thanks (sorry if the question is a bit wooly).

---

Xcode does not provide any such guidelines to do so, but there are some other software that can be used.

You can use MockApp or omni graffle to design your apps. You can also use photoshop but it might be an over kill if your app is small or low budget or if you dont know how to use it.