Geometric transformations on JPG images that simply involve re-arranging existing pixels (rather than interpolating new ones)
can be performed in a completely lossless manner.
They can be performed hundreds of times with no loss whatever.
Such operations include rotations of 90, 180 and 270 degrees, joining left/right images, decomposing side-by-side images to left/right pairs and swapping left/right images.
The input images may be baseline or progressive and if they are of different sizes or the height/width are not multiples of 16, SPM applies suitable cropping.
The output images are always a multiple of 16 pixels in height and width and in baseline format.

Navigate to the folder (or folders) of JPG images that you wish to convert and choose selected files or all files.
Choose the desired operation or 'Rotation(Auto)' if you wish SPM to use the embedded orientation tags.
If you are creating triplet images,the image shown in the preview is the outside images.



Check 'Swap Left/Right' to make the other image the outside images.



If you check 'Copy all extra markers include EXIF', SPM will also rebuild the embedded thumbnail image.
This will subsequently allow 'Windows Explorer' and SPM's 'File Property' to display the thumbnail image in correct orientation.
In the case of 'Windows Explorer', the actual image will now be correctly displayed.
Simply loading and then resaving images that have orientation tags and choosing 'Rotation(Auto)' will ensure they are correctly displayed by 'Windows Explorer'.

Choose an existing folder for the output images or enter the name of a new folder that SPM will create.

'Convert All Files' or 'Convert Selected Files' as required.