How does UIImage work in low memory situations?

Question

According to the UIImage documentation :

In low memory situations, image data can be cleared from the UIImage object to free up memory in the system.

Does anyone know how this works? It seems like this process is completely transparent and will happen in the background without input from me, but I cannot find any final documentation anyway.

Secondly, will this data cleaning happen when the image is not uploaded by me? (I get an image from UIImagePicker).

Here's the situation: I take a picture with UIImagePickerControllerand immediately take this image and send it to a new one UIViewControllerfor display. Sending the original image to the new controller crashes my app with memory alerts in about 30% of cases. Resizing an image takes a few seconds, a time that I would prefer not to waste if I have a third option.

Answer 1

I think this is the answer. The documentation for initWithContentsOfFile:says:

This method loads image data into memory and marks it as being cleared. If the data is cleared and needs to be reloaded, the image object again loads the data from the specified path.

UIImage , , - .

Answer 2

: , :

[NSData dataWithContentsOfMappedFile:]

. .