Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
I think maybe you should post a picture of the effect you are trying to achieve.. by saying "yellow up and image without turning everything else yellow" doesn't make a whole lot of sense.
About the skin tone thing, when you just turn the yellow up on an image, or any color for that matter, things like that will happen. You also have to take into account contrast, curves, etc.
But again, see if you can find an image with a similar effect, it may be easier for us to understand exactly what effect you are going for.
Oops sorry, I meant to yellow up an image without affecting certain parts of an image.