iOS - Caching and loading images asynchronously
I know that this thread has been answered, but I have tried a library that has worked great. I was using ASIHttpRequest before and the difference is big.
https://github.com/rs/SDWebImage
Also, if someone needs to Resize or Crop the remote images, and have the same features that SDWebImage provide, I have integrated SDWebImage library with UIImage+Resize library (by Trevor Harmon), and created an example project. I modified the code of SDWebImage to deal with transformations (crop, resize).
The project is public on https://github.com/toptierlabs/ImageCacheResize. Feel free to use it!
EDIT : ASI has been deprecated now but @Tony's answer has a link to a library that seems to do most of this (disclaimer - I've not yet tried it and am going by @Tony's recommendation!)
ASIHTTPRequest does all of that :)
All you would have to do is add something like to the success callback
UIImage *image = [UIImage imageWithData:[request responseData]];// If the image is nil ASIHTTPRequest will let you remove the data from the cache// but I can't remember off the top of my head how. Checkout the docs!
EDIT
And when you've finished it, you could always pop it onto github for the rest of us . . .
I had a look recently for the sort of thing you describe -- either a general data cache, or an image centric one -- and didn't find much of interest. So you may have to roll your own to get all those features.
There's a various blogs posts and things detailing such things, such as http://davidgolightly.blogspot.com/2009/02/asynchronous-image-caching-with-iphone.html.
I take it you've considered the Three20 library? I don't think it would cover your requirements though.