Lmao looking at all the posts above you guys are hilarious .I guess by enhancement he needs you to make the picture better in terms of pixels ,size and overall an HD quality .What most of you've done just applied effects by adding some brightness contrast and other filters .Not sure if OP actually wants that but I think he needs a picture better in pixels which is impossible because you cannot add more pixels into the original picture as they cant be regenerated but yeah it can be over written as above posts .
You can make a picture higher quality. It is called a vector - a image type that can be resized to any size and don't lose image quality. But that is mostly for logos.
It is very expensive for bugger pictures, because the editor/designer needs to remake every singe element with mathematical algorithms or retrace every single line/form with geometrical rules.
In my opinion the price won't be lower than 0.5 btc for a vector of this size.