In Advanced editing, we are able to "clone out incidental power lines, twigs, dust specks, stray hairs, and similar minor imperfections".
In the "100 Years Old" challenge, let's say there is a small plaque or other sign that is visible in the composition. Being at a historic place there are many such signs that give stats on the historic building or artifact.
Please submit a ticket (under the Help menu) to the SC with before/after versions of the image and a decription of your editing steps, and you will probably get a fairly reliable assessment of whether the object(s) you want to remove is/are "incidental" enough.
This rule is based on a subjective interpretation and it's quite unlikely that all SC members will agree on any particular image.
That's the direction I offered, and it's a good general guideline if applied with common sense. A background jet contrail or a tree trunk along the edge of the frame might be visible even in the thumbnail and still be minor enough distractions to clone out, while a mosquito could be major enough to keep in a portrait if the model's looking at it cross-eyed on his nose. It's a matter of visual prominence... a question of, "Hey, where did that [cloned out thing] go?" At a glance, an object supported with fine fishing line appears to be levitating, while one held up with rope is obviously hanging. When in doubt, submit a ticket for opinions.
Which I did last night and haven't heard a thing as far as a response or guidance goes. I just replied to my original ticket with another comparison image example. I hope to hear something before tonight's deadline!
