Hello, I open JPG from my camera do some editing and in the photoshop looks good, however when I save it as jpg, it looks totally different. Any advice? Thanks in advance.
It looks different where? In Photoshop?
What is the image’s Colour Space?
Is the profile embedded?
What are Photoshop’s Edit > Color Settings?
Please set the Status Bar to »Document Profile« and post a more meaningful screenshot.
I seem to have a similar issue.
I am comparing an unedited sRGB image from the camera and the same image in Faststone viewer. I am running PS CC 2018 on Win 10, both it and Faststone are up to date. PS workspace is sRGB. Colour settings and an example follow.
The monitor is a Dell 2407WF which has been calibrated using DasplayCal and a Spyder 5, the difference exists with the profile enabled or disabled.
I rarely print but the difference makes processing confusing
Also appreciate any advice. Thanks
I am comparing an unedited sRGB image from the camera and the same image in Faststone viewer.
Is Fasttone Viewer Color Managed?
If you were comparing Photoshop’s image display to that of applications that are not you would be »comparing apples and oranges«.
To test the issue please assign the image the monitor profile in Photoshop – does it appear identical (or close to identical) the FastStone Image Viewer display?
Alternatively please check if FastStone Image Viewer’s Color Management is enabled.
Thank you, my color settings is this: 
The image is RGB colors 8bits. But I don't know how to find out what is the image color space. The photo looks good when I edit in photoshop... I just found out that even the source image looks different in photoshop then when I see it in the Photo Viewer (I would say it looks better in photoshop) so I think is has to do something with Windows photo viewer.
The image is RGB colors 8bits.
But what is its Colour Space?
Again: Please set the Status Bar to »Document Profile« and post a more meaningful screenshot.
I am comparing an unedited sRGB image from the camera and the same image in Faststone viewer.
The Faststone viewer claims to be color managed, but it's not. It says that the CMS works for jpgs and tiffs with an embedded profile, but it's obviously not converting colors from the embedded profile to the monitor profile, which is required for color management to work.
The free Irfanview image viewer has color management that works - as long as it is enabled under Settings.
The Windows Photo Viewer (not the Photos app) is also color managed.
I wrote in my previous post that I don't know how to find out color space. No clue what is that
I have specifically asked you to do something twice, have I not?
That would have indicated the Color Space.
RGB is a Color Mode, but many RGB Color Spaces exist – sRGB, Adobe RGB, eciRGB v2, …
Similarly many CMYK Color Spaces exist: ISO Coated v2 (based on FOGRA39), U.S. Web Coated (SWOP) v2 etc.
When talking about images calling them »RGB« without defining the RGB Space is close to meaningless as this would not actually make clear how a pixel with particular RGB values is intended to appear.
Just like determining the actual distance between two places on a map is not feasible without knowing the map’s scale.
antonyb, you need to stop right there and go back to start. Your Photoshop color settings are all messed up.
First of all, never set Color Management Policies to "off"! It's a legacy setting from the stone age and I wish they would just remove it. Color Management Policies should always be set to "Preserve Embedded Profiles". So do that, and never touch it again.
If you want Photoshop to temporarily disable color management for testing purposes, use Proof to Monitor RGB.
Second, ColorMatch RGB is outdated and I honestly don't know of anyone still using it. Until you have more experience, I'd recommend sRGB as RGB working space. But the working space is just a default - the embedded document profile should always override the working space. Unless you have color management policies set to off! In that case, the working space is assigned to every file.
Long and short: In the settings rolldown at the top, pick one of the "General Purpose" presets. This will reset/restore your color settings. When you've done that - don't change anything until you have lots more experience and you know what you're doing.