A guide to your archive

Keep the back with the photograph.

PairSort renumbers files that already have matching names. It recognises the filename ending you choose; it does not identify matching pictures by looking at them.

Start with one album

1. Add the scans from one album. Files appear in natural filename order: Photo2 before Photo10.
2. Enter the ending used for backs. The default is _b. For example, Photo3_b.jpg matches Photo3.jpg. Matching ignores capital letters and the file extension, so a JPEG front can have a TIFF back.
3. Choose a new prefix, starting number and number of digits. Select “last to first” to reverse the order. Backs always move with their fronts.
4. Review the original and new filenames. Untick a whole photo group to leave it out, or use × to remove a particular scan from this batch.
5. Download the ZIP and extract it into a new folder. The ZIP includes a CSV filename list so you can trace every copy back to its original.

An album scanned backwards

There are four photographs, but only Photo3 has a scanned back. With reverse order, prefix Album, three digits and a start of 1:

The back does not use an extra number. Gaps in the original sequence are closed when new numbers are assigned.

When a pair needs attention

Back with no front: check that the names match exactly before the back ending. Photo03_b.jpg does not match Photo3.jpg. Correct the source filename, choose the right back ending, or untick the group to leave it out.

More than one front or back: the same name may have been selected twice, or two albums may use the same filenames. Remove the extra file or process those albums separately. Download stays unavailable until every included group has one front and at most one back.

A photo without a scanned back is fine. A file whose name happens to end in _b will be treated as a back; choose a different ending if that is not how your album was named.

Your files and downloads

Originals are never renamed or overwritten. PairSort puts their exact bytes into a new ZIP under the names shown in the preview. It does not resize, re-encode, rotate or strip image metadata. A thumbnail may appear rotated according to the image’s metadata; the downloaded file itself is unchanged.

JPEG, PNG, WebP and other image files can be added. TIFF and HEIC previews depend on your browser; an extension label may appear instead, and renaming still works. Each batch can contain up to 1,000 files and 250 MB total. Larger archives can be split into albums; continue the numbering with “Start at”.

Files are kept only in this open tab. Download before closing it. There is no saved cloud album or account.

Open PairSort →