Retouch Pilot Lite is a basic tool for cleaning up a photo by removing very small imperfections (scratches, spots and so on).
Perhaps you've scanned a really old family photo, for instance. After 50 years in a forgotten photo album the print will have degraded, and you'll almost certainly see white spots where the original detail has been lost. You can clean this in a regular image editor, with a little work, but Retouch Pilot Lite makes the process far easier.
After a simple installation, launching the program presents you with a basic interface. This has a very few standard editing tools - resize, crop, rotate, flip and so on - but the most interesting one is the "scratch eraser".
Select this, move your mouse over a photo, and the cursor changes to a circular brush. Click on a spot, or click and drag over a scratch, and in theory at least it should automatically disappear, without making a noticeable change to the rest of the image.
We say "in theory" because this really does depend on the source photo, and the size of the defect. When we tried it with a faded old black and white photo, for example, it removed tiny spots and similar problems perfectly, with no problems at all. We then used it to try and remove a larger physical detail from a colour image, though, and the results were terrible, just totally unusable.
If you're already an experienced graphics editor, then, familiar with a clone brush and used to repairing minor problems, Retouch Pilot Lite 3.5.3 has little to offer.
But, if you're not sure how you'd remove tiny spots and scratches from an image, or you're going to have to remove a lot of them and need a quick way to do it, the program may prove useful, and it's certainly worth a try.