If there were strict guidelines as to what an image is supposed to be representing in an open theme, then abstract photography would have to be banned for the most part.
I have no issue with images like that frog one in an open comp, just as long as it wasn't nature oriented in any way(ie. reptile based, or nature or animal or whatever).
As Kym commented about the merits of that frog photo it's place in the comp that it won .. ie. all good.
So the key point here is not to deceive folks with photos that simply aren't a reality, when the reality is the main point of the image.
Ergo. if the image presented is supposed to be a photograph(ie. and not a digital creation!) then you would be allowed the courtesy of editing that photo in a way that the camera could(ie. colour tones etc).
As an extreme example of this editing: we humans can't see in IR(infrared) and need devices as such to see it(for what it is). False colour IR(the colourful looking IR) doesn't exist in any world, but a camera can create it.
What we'd see in terms of colour in IR is simply black and white images, with varying degree of grey tones. This is what IR actually is.
But the camera can capture false colour IR due to the capability of the sensor, the ability to render those colour tones and the choice of filter used.
Creating an IR image in this false colour manner doesn't preclude it from being labelled a photograph tho, even tho it looks surreal(or unreal) to us. there are many creatures that can see in this IR manner(apparently).
A version of reality is still a reality.
Two seconds ago was a reality for me(and for you) but that moment has passed now, it doesn't mean that that reality 2 sec ago never existed.
BUT!.... in your two image examples at the start of this thread(and then compared to the actual photo) they aren't a reality, most likely they never have been, as I'm assuming that the land area where the car park exists has always existed.
The car park and the people may have changed over time(since that castle was built), but it appears that the land in the foreground has existed for as long as the castle has.
Had you captured that castle from the other side, where it appears to be all watery, then that's a reality that does exists. Edit that with as much tonal manipulation as you like .. to me it'd still be a photo.
The first two image presented are basically digital renderings .. ie. not photographs.