由于内存压力，iOS应用终止

I am trying to use image files with my app. These image files are compressed in a .zip-file which is opened from the user from the Mail App or Safari. The .zip-file (which contains the image files) is then unzipped by "SSZipArchive". This works without any problem for smaller files (e.g. 5 images, 10KB). But for bigger files (1900 images, 20MB) the app crashes and it is hard to figure out why because it only crashes when the app is not debugging and not watched by Instruments. A few times I got a crash while using the debugger but only when I opened the .zip-Archive from the Mail App. I then got the message "App terminated due to memory pressure".I am trying to use image files with my app. The