Like magic, the element that you select will disappear from the photo - just give Image Mender some time to run an exhaustive analysis of the image. That means you can use the program to get rid of details both big and small.
It produces spectacular results. You can barely see any trace of the eliminated object. Image Mender can work with the following file formats, among others: JPEG, TIFF, BMP, PNG, and TGA.
One alternative to Image Mender is PhotoWipe, which does basically the same thing, but with less precision.
Does not allow you to save your edited images.