Scaling the image -- Quality check

Does scaling the image using: image=[UIImage imageWithCGIm开发者_开发问答age:[image CGImage] scale:2.0 orientation:UIImageOrientationUp]; reduces the image quality?

If you mean something like compression artefacts then no, cause those are added when it comes to saving to disc in a specific format like JPG.

There is also a yes, because you double the dimensions of the image which will interpolate the pixels that never have been there, this will always look blurry starting at a certain point.