Are you asking anyone in particular? Without looking at a photo in particular, I couldn't tell you what they most likely did. There are many ways to achieve the same result. The features you might be referring to in particular are the white balance, color saturation, and the exposure. Usually white balance and color saturation are not manually adjustable except for the higher end cams. I have a couple nikons and I can manipulate the white balance (same thing as the K ratings on a computer monitor), to give me more of a certain color or to compensate for unnatural lighting (a flash). This can sometimes result in colors being caught that arent normally visible. Color saturation is like the simple color adjustment on your TV. Examples of low-no saturation would be the B&W or sepiatone modes on many cameras. Oversaturation can result in colors bleeding and making percieved 'lines' fuzzy, especially the red hues. The exposure, I shouldnt have to explain that one, besides being a comprimise between affecting depth of field and speed, (manipulation of the aperture and shutter), technically will absorb more chrominence (color of light) as it absorbs luminence (magnitude), but usually will not end up makng a photos colors change from what you might percieve with a naked eye, although keep in mind that while your eyeball may have trouble picking up color as things get darker, a camera can pick up colors in near dark by just having a longer exposure. I have taken long exposure photos in near darkness, and while I may percieve very little color at these levels (human limited nightvision kicks in so everything ends up bluer/greener), the camera picks up full color as if it were daytime. And as if the camera didnt have enough to manipulate, I have taken very dark photos (wanted a high speed for movement, yet not very much light & didnt want to use flash), and while my cam wouldnt show anything more then a picture of shades of black...I used adobe photoshop to "raise the lights" to a level that looked like daytime. Now, for some reason, when I manipulate photos like this, the software seems to make the colors extra gaudy (long explanation as to why, but it is actually quite natural if you think about it, if you try to raise the luminence of a photo, the chroma will be enhanced as well, even though it may not be needed). And the methods manipulation dont end there...
