Originally Posted by djskinner
The reason you were asked if it was a game is because games as typically a little more difficult to get to support the different screen sizes. If you're developing a music app using mostly standard iOS components then your developer is probably not going to have to do any extra work to add iPhone5 support (for example, a full screen table view will just expand to fill the new screen space) unless you want the iPhone5 to have significantly different graphics (see below).
What I tend to do with graphics (as a developer) is to add only the highest resolution graphics to the build (i.e. the retina ones). iOS does a good job of scaling down images for non-retina screens. This helps to keep the add size low (significantly). In fact, I'm currently adding iPad support to our game and where the iPad graphics are just larger versions of the iPhone ones, I will be only adding one file for that graphic - the larger iPad version.
This is why @ovogame's point is important. If things are going to be scaled down to half the size (whether you let iOS to it or do it in Photoshop) then you better make sure that the positions and sizes of your slices are on even pixels. A graphical asset which is 131px for retina is going to scale down to 65.5px for a normal screen. This half-pixel is obviously a problem (although it reality its not that bad).
Where the graphics do need to be different (either to support iPhone 5 or iPad) then obviously you're going to need to send separate slices for these elements. In all but the most simple cases this is going to require a separate screen file (XIB) for iPad/iPhone 5.
Hi DJSkinner, thank you for your detailed explanation. I think my developer is trying to rip me off, or he's a inexperienced one. So you mean that IOS can automatically scale down large graphic files !? I only have to slice up one set of graphics?! is there any advantage to providing the three separate sizes ?
320 x 480px - iphone 3
640x960px - iphone 4
1136x640px - iphone 5
ANd if I provide just the one set of graphic files at the largest size 1136x640 , do I still name the files with the suffix @2x ?
ANd is my developer also wrong about having to create new layout files (xib files) for new retina displays/devices ? He says the UI work is at least 30% of total work, thus why he wants to charge me extra money for this. Again I think he is wrong, the graphics for all devices are the same only the resolution is different. SO the layout files for each iphone should be the same? Am I right? what new layout files does he need to create? Especially if IOS can automatically reduce the graphic size or if I provide him with the reduced graphics.