Solution #1:
Just remove the release statement. ARC will manage it for you.
[imageArray release]; // remove this line
ARC is Auto Reference Counting. As opposite to manual reference counting.
There are a few great videos of talks from WWDC. I can provide  the link if you wish to watch them.
In Transitioning to ARC Release Notes, see ARC Enforces New Rules:
You cannot explicitly invoke dealloc, or implement or invoke retain,
  release, retainCount, or autorelease.
The prohibition extends to using @selector(retain),
  @selector(release), and so on.
Solution #2:
If you do not wish to convert the code to ARC (e.g. you are not writing a new application, but are maintaining an old one / or you imported so much code that moving to ARC is not worth it) you can disable ARC.
- Disabling ARC for selected files To disable ARC, you can use the - -fno-objc-arccompiler flag for specific files. Select the target
and go to- Build Phases->- Compile Sources. Edit the- Compiler
Flagsand add- -fno-objc-arc
 
- Disabling ARC for the project 
 Source:How to disable Xcode4.2 Automatic Reference Counting
 - 
- Click on you project, in the left hand organizer.
- Select your target, in the next column over.
- Select the Build Settings tab at the top.
- Scroll down to "Objective-C Automatic Reference Counting" (it may be    listed as
- "CLANG_ENABLE_OBJC_ARC" under the User-Defined settings group), and    set it to NO.