Lossless rotation of photos using Windows Photo Viewer? (XP vs Win7)

If I wanted to rotate photos in XP using Windows Photo Viewer I was told, that it wasn't lossless rotation (so, worse quality in the rotated photo).

What about Win7 and Windows Photo Viewer? Is it lossless rotation of jpegs in Win7?

Solution 1:

Short answer:

If the dimensions of the image are multiples of 8 (or 16 if chroma subsampling is used) then the rotations are lossless. Otherwise it is not possible to rotate the image without recomputing the blocks i.e. recompressing the image, which is lossy.

Full details:

See here for the rest of that great explanation about lossless JPEG rotation and Photo Viewer under Win 7.

I suggest you try Xnview as your image viewer, it has many interesting functions that I particularly like:

• advanced options for slideshows
• contact sheets creation from pictures folders
• supports many more file types than the windows default one
• quick edit pics by adjusting brightness/contrast/exposure/color
• multiplatform

Make sure you comply with the licence because Xnview is not free for commercial use.