By default, FotoFinish uses Smart Resampling to resample images that you reduce in size. This type of resampling blends details taken out of the photo with details that remain for a smooth appearance. If you make your images larger (upsample), Smart Resampling by default does not apply resampling, it simply resizes by stretching pixels.
If you want to force FotoFinish to resample your upsized image, click on More in the Resize dialog and from a drop-down menu of options choose Resample Always. This will resample images scaled both up and down.
If you don’t want FotoFinish to apply any resampling, choose No Resampling from the drop-down menu of options. This can result in your downsized images looking clunky and blocky. Try both options if you are unsure which will give the best results.