I cannot understand why there are so many views of these questions, with no replies.I have never seen tutorial. The method below, however, while tedious, is always completely accurate and is quite satisfactory for careful viewing.I suggest using clone tool in Photoshop, cloning from as close as possible to flaw; in case of sky, be very careful not to have cloning point any higher or lower than flaw. Any remaining evidence of flaw can often be airbrushed over, using a rather transparent setting f...

Don't worry that file size is larger than specified that it should be. Save the image as jpeg, and then have a look at it in its folder and you will see that it is, in fact the file size you wanted. Use lower resolution than 300, usually 75, but keep the 1000px shortest side. I assume that this is a spec for entering image for exhibition, and they usually want 75dpi, unless otherwise specified. They usually give very poor directions for accomplishing what they are asking for!