hd images, and app size - objective-c

Question

i have 2 issues.
my app has a high quality images, and i enabled the retina display(using cocos2d), so every png has the hd : image-hd.png .
my first question is, if want it to fit also iphones under 4 (3gs) i must have all my images again in the 320x480 without the -hd ?
i have sooo many images, and this way seems strange to me, cause it doubles the app size!
another thing. my app size on disk is BIG, but i have discovered that there is a folder init that called: build, which is 136Mb ! it has simulator and debug files that are not mine.
how would i get ride of this folder that is so big ?? my app is 30mb only !
thanks a lot

Answer 1

i must have all my images again in the 320x480 without the -hd ?
Yes. If you want your game to work with non-Retina devices, then for each xxxx-hd.png you must provide a corresponding xxxx.png file.
this way seems strange to me, cause it doubles the app size!
It doesn't double it. It depends a little on the type of files (PNG, JPG) and how well the images can be compressed. Uncompressed, an SD image is a quarter of the size of an HD image. So you're more likely looking at an increase of app size by 25%. If your HD assets weigh in at 100 MB, your SD assets will add roughly around 25 MB to the app size.
my app size on disk is BIG, but i have discovered that there is a
folder init that called: build, which is 136Mb ! it has simulator and
debug files that are not mine.
These are temporary build files created by Xcode. Don't delete them because Xcode will recreate the files anyway.
The size of your .app is the only file size you should be considering. Furthermore, you should ignore the size of your .app in debug builds, which is what you've been looking at. The only app size from which you can determine (or guesstimate) the final app size on the App Store is the app created by an Archive build.
Run Product -> Archive with a iOS device selected as your current configuration (otherwise Archive is grayed out). When it's done, the Xcode Organizer will open and highlight the newly created archive. Right click it and select "Show in Finder". There may be several .xcarchive files in this folder, select the latest one and right click it, then select "Show Package Contents". Navigate to Product/Applications which will show your .app and its size. This is the only size of your app you should ever give any consideration.
However, this is not the final size of your app on the App Store, since the .app bundle will be compressed (making it smaller) and at the same time the executable will be crypted (making it impossible to compress). I once wrote an article about how to determine your app's final App Store size that I think still holds true today. In essence, you copy the .app bundle, remove the executable from the bundle, compress the bundle, then add the size of the compressed bundle and the size of the executable and the result is a good approximation of your app's size on the App Store.

Answer 2

You need to give a name for HD image with prefix #2x, for example image#2x.png. Leave normal name for images in order to support lower versions of iOS - image.png. In code or Interface Builder you have to use only normal named images (all another things will be executed automatically).

Answer 3

The short answer to the 'images' part of the question is YES , you should include the normal sized files. The artwork is probably different with the two resolutions (I am not a graphics expert, but i suspect there is a lot more to it than resizing the image). The whole point of implementing the "-hd" suffix was to have the ability to deploy a single bundle that works seamlessly for Retina and non Retina displays. I just had a requirements change to go from SD to SD+HD on one of my products ... errr ... now both the artists and the softies are in a mad rush to do just that : create the artwork and make certain all is well (ie no missing resources). Best of luck with your own requirements change.