I'm wondering if/how I can change background color of the following images.
I don't like the blue background color of the second image but I want to keep the shirt color (jean/blue color).
Please note : I have used Photoshop CC
Make a selection on your shirt. Press **Ctrl + Shift + I [windows]** for an inverse slection Press **Ctrl + J** to make a copy of the selected area. Open Camera raw filter **Filter > Camera Raw Filter** Press **HSL/Grayscale** option can be find in top menu bar of camera raw filter Select **HUE** and adjust blue to your choice of color
Also please come through these screenshots for an easy tutor.
In Photoshop you should select the unsatisfying color area and change its color to another. Or you shold select the good area, cut it to the clipboard, paste it into a new layer and replace or modify the underlying (=bad) layer.
This is easy to write. Unfortunately computer programs, like Photoshop don't have any common sense and human knowledge. The problem is "how to define the border between good and bad areas". Photoshop knows nothing about skirt, jeans, hair, skin, background wall etc.... You must tediously draw the selection border yourself or carefully in very small chunks erase the bad areas. After that you still have to redraw something unwantedly erased, typically the sparse outer parts of the hair.
Sometimes there is a clean, steep change in color or luminosity at the border. In that case you can use automatic tools like Magic Wand, Magnetic Lasso, Quick select tool or some third party masking plugin. Exactly the second photo is little easier in that sense and seemingly you already have got it modified.
But the job is not well done. The person in the background should still have a blue jacket. Otherwise the photo loses its impact - it's not any more obvious that somebody gladly shows a selfie.
Photographers often take their photos in a place (=lights and background) where clean and steep borders will be formed. But very often, like now, satisfying results for picture 1 are achieved only by hard work. You must learn how to use Photoshop's selection tools and how to fix the deleted fine details (=hair).
If I were forced or hired to do this job, I would draw the selection border as a clipping path between the good and the bad. Nobody has the time and tolerance to draw the path also around the finest hair parts, so I would redraw the lost hair.
I recommend to read some Photoshop learning book and watch "how to" videos in YouTube. This website also has several discussions about this. Most important is to practice in simple cases at the beginning and to understand how the tools work. If you have no former skills on this subject, it will take weeks to reach even the lowest acceptable speed and accuracy to do thislike jobs. Only a genius can be at home in this job from the very beginning. Sorry for that.
btw. This is a screenshot of the easier case:
The solution is essentially the same as Rajeev's. Raw filter is not used, but color adjusment layers are created. Layer masks are used to limit the area which is affected by adjustment layers.
Finally I have a coarse, but easily created solution to picture 1. I used Topaz Remask plugin. It allowed me to paint a coarse border zone over the area where the actual clipping path should be drawn. Then I pointed which side of the border should be removed. Remask did it's best to find the proper borderline. On unsure areas you can see some fuzziness. This is the best that can be achieved without drawing the precise clipping path and maybe by redrawing lost details such as sparse hair parts. It took less than 5 minutes to create it. The result is good enough for smartphone screen but definitely too fuzzy for high resolution printing or for big ultra HD screens.