Application for lossless JPG rotation

10-10-20

Can anybody recommend an application for rotating JPG's without loss?
I would like to do it from the explorer window, or the right-click menu.

I don't have any photo editing suite, not that I don't need one, so I want to preserve the quality as best I can.

RoryW

picassa is free but as for whether it gives loss, i dont know

Thirdfox

I think any "save" with jpg files incurrs loss - so I don't think there any way of doing that...

You could convert the image to TIFF first (a lossless format) and rotate it, then convert it back to jpeg.

Honestly though - I do not see much loss even after quite a few saves (always save on maximum jpeg quality).

Roen

Just make a few copies of the original and work off those. If you're going to be making multiple edits to the one jpg over time then it's time to look at other means of saving/processing.

Fenster

Use the Gimp.

Any half-decent editor will save at the compression level you set it to.

10-10-20

Here's a list of apps which do it in a lossless way - http://sylvana.net/jpegcrop/losslessapps.html

EDIT - Ah here - found what I am looking for...
http://www.anryhome.com/software/jpeglosslessrotator/
I'll test it out and report back tomorrow!

Alun

Thirdfox wrote:

I think any "save" with jpg files incurrs loss - so I don't think there any way of doing that...

Wrong

You can only do it though on an image where both dimensions are divisible by 16 (which most, if not all, images straight from the camera do). Many apps that do rotation will automatically detect this and use whichever algorithm is more appropriate (usually warning you if lossless rotation is impossible).

You can also do lossless cropping and flipping about either axis, again, if the image dimensions fit the "divisible by 16" criterion.

Thirdfox

Learn something new everyday...but how did you come about this information?

10-10-20

Have a look at 'users questions'...
http://www.anryhome.com/software/jpeglosslessrotator/

Ghost Train

http://www.irfanview.com/ does lossless jpg rotation, will need to download the plugin pack for it to work

Alun

Thirdfox wrote:

Learn something new everyday...but how did you come about this information?

A long time ago I did some programming using various graphics formats, and it cropped (no pun intended!) up then. It's quite clever stuff, as the lossless transformations can be done merely by manipulating the file itself. The image itself is at no point, decoded or re-encoded so no loss of quality.

Thirdfox

Interesting...but my Nikon saves in 3000x2008 format - doesn't divide evenly by 16

10-10-20

Neither does my FinePix S7000...

Alun

Thirdfox wrote:

Interesting...but my Nikon saves in 3000x2008 format - doesn't divide evenly by 16

Are you sure you haven't got those dimensions mixed up a little? I have a Nikon too, a Nikon D70s, which saves in 3008x2000, both of which are divisible by 16.

Thirdfox

Sorry, it seems that I inputed the incorrect numbers into the calculator (I mistyped the 3008x2000 in my previous post). Double