uitableviewcell resize image - iphone

Question

i load data in a tableview, each row have a simple picture 500x300px that go resize to size of cell.
Is possible resize the images?
tableview.m
NSString *filePath = [[NSBundle mainBundle] pathForResource:receip.image ofType:#"jpg"];
UIImage *image = [UIImage imageWithContentsOfFile:filePath];
cell.imageView.image = image;

Answer 1

I assume you mean resize them before putting them in the cell to improve performance?
You can do this with core graphics as follows:
//define desired size
CGSize size = CGSizeMake(100.0f, 100.0f);
//create drawing context
UIGraphicsBeginImageContextWithOptions(size, NO, 0.0f);
//draw image at new size
[image drawInRect:CGRectMake(0.0f, 0.0f, size.width, size.height)];
//capture resultant image
UIImage *resizedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Be warned though that is a computationally expensive task. You'll probably want to resize all your images in advance, possibly on a background thread, and store the resized versions in an array. You definitely do not want to stick the code above in your cellForRowAtIndexPath method, or your table scrolling performance will be diabolical.

Answer 2

If those images come from an external source (say the web). It's better to first cache the original file and then (like explained by #Nick Lockwood) resize them (remember retina displays need twice the width / height for hi-res displaying). And after that process is complete you can send a signal that the "download" is complete and carry on showing the UITableView
If you already have the images in your app bundle I suggest you make a thumb version of that and add it to your bundle. For better performance o'course.