NSString *fromName = [NSString stringWithFormat:@"image%d", i];
NSString *fromPhotoName = [[NSBundle mainBundle] pathForResource:fromName ofType:@”jpg”];
UIImage *fromPhoto = [UIImage imageWithContentsOfFile:fromPhotoName];

Thanks again,
CPL

The only problem I have is that the animation goes really fast now. I put a wait() but it doesn’t seem to work. I use a CATransition to switch between two views. Do you know if there is a way to make the animation run slower? I tried the CAtransition.duration but it doesn’t work the right way.

Again a 1,000,000 THANKS !!!!

So, for one of my Apps instead of using UIDevice to determine whether to use Layers or not use Layers depending on the iOS version number. I decided I would get the actual device model using sysctlbyname. Although UIDevice will also give you the model it does not distiguish between actual models of the iPhone. Instead it just tells you it is an iPhone. sysctlbyname will give you the additional information you need to distinguish between the different types of iPhones.

Here is my set of Defines for what sysctlbyname returns (It returns a string…I don’t know if this forum is going to post this properly, but I will try anyway…all you really care about is the string literals):

#define DIDRST_Unknown @""
#define DIDRST_iPhoneSimulator @"i386"
#define DIDRST_iPhone1G @"iPhone1,1"
#define DIDRST_iPhone3G @"iPhone1,2"
#define DIDRST_iPhone3GS @"iPhone2,1"
#define DIDRST_iPhone4 @"iPhone3,1"
#define DIDRST_iPad1 @"iPad,1"
#define DIDRST_iPodTouch1G @"iPod1,1"
#define DIDRST_iPodTouch2G @"iPod2,1"

So, now you can determine which devices you want to support with Layers and which you want to support with the older approach. For instance, I wanted all the older devices to NOT use layers even though some of them may have been using iOS4. This was only an issue for one of my apps. On other apps I wanted any device using iOS4 to use Layers (in which case I used UIDevice instead of sysctlbyname).

Sadly I know someone out there in Internet World there is someone that will need this post (I sure was, but couldn’t find anything). Hope they find it here cause this thread is the extent of my helpfulness.

Remember this is only if you run into trouble with your animations. If the images are small enough you might not see any substantial slowing and then you can just keep doing what you are doing. But if you upgrade to OS4 and your animations start to crawl then this is how you can fix it.

Sooooooo, if your animations all of a sudden slow down to a crawl once you upgrade to OS4 then this is why that is happening. You need to switch your animations over to using a sublayer and updating its contents.

Mind you there is still good reason to get your png file sizes down. There is a limit to the app size that can be downloaded through ATT’s network. I have found that people want to buy apps when they are sitting outside with friends or some such. That means that if a user has a choice between waiting until they get home to buy your 11mb app and someone else’s 9mb app that they can download emmediatly they will by the 9mb app (I think the limit is still 10mb, but they may have changed it to 20mb recently…but I don’t think so…I think it is still 10mb). So, smaller png files sizes can be helpful in that regard (there are lots of tricks you can do to bring that down considerably). But those sizes don’t matter when you are trying to animate. Actually, they can hurt your animation speeds because there is more work decoding them.