I did consider minimal but how I can track that? I want to make this for everybody not just the people who are into photography. Some people may not know even minimal post production so it's not fair to have an unfair advantage. If it becomes a problem then rules can always be changed later on. I am just trying to do something fyn for EVERYONE.
You can only eyeball it and make judgments. Those with a lot more experience in Photoshop and whatnot could help you make a decision if there's any question about how much work was put into a photo.
Ultimately all pictures go through PP. Period. The raw data from the sensor of a camera has to be interpreted to produce a JPG. A Canon HS 100, for example, is a $120 camera that basically has a full Photoshop routine built in. Every time you snap the shutter, the camera boosts the contrast, corrects the exposure, applies highlight reducing and shadow boosting, adjusts the brightness, runs it through a sophisticated noise reduction routine, and applies a sharpness boost. After all that it exports this data through a color interpretation machine to apply a color space and finally a JPG compression routine.
It does all that every time you take a picture.
My low-end $500 Canon DSLR, in RAW mode, doesn't do any of that. The same picture that looks fantastic from the HS 100 would look dull, lifeless, and almost out of focus right from my camera. It just captures the raw data. The RAW image must go through all that processing on the computer side. Canon includes some software (PhotoEX or something like that) but like most people who aren't braindead I use something else instead. All of my photos get imported through Adobe Photoshop Lightroom which applies all of the things the HS 100 does, but it lets me tweak it a little bit per picture.
Ultimately you can't know precisely how much PP the image has gone through. But you might see "Adobe Photoshop" or something somewhere in the EXIF data.