Re: Rotating photos shrinking file size and video trimming is it lossless or lossy
If I take a photo and rotate the image the file size decreases by half.
I am assuming HTC rotation isn't lossless?
Probably not. Most ways of compressing pictures use lossy algorithms. (Program compressors are lossless, because a change n a sijngle bit can cause the program to crash. So you can zip a picture to make it smaller - to send it by email, for example - but you can't view it with compression in the original quality.)
Also, when trimming videos is this lossless or lossy?
If you use a program that allows you to save the edited picture at 100% quality, it's like cutting off the edges (or wherever you're trimming). The part of the picture you don't trim away stays the same, the resulting picture is just smaller.
If you trim it, then save it as the same size the untrimmed picture was, it's the opposite of lossy - elements are added to fill in the blanks (you can't create data) or the pixels themselves are larger (depending on the program). In either case, the quality is reduced.
For the most part, anything you do to a picture other than editing it pixel by pixel will reduce the quality.
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