How to change background of the pic in the wanted RGB in writer?

Please, in word there is option, thatwe can change background of a pic (f.e. from internet), so that we get the right tent RGB, and it authomatically marks what is the pic andwhat is the backgorund .

Please, how to do the same in writer?

In word we just had to click to pasted pic and there popped up the tool for manipulation with the pic.
Please, how to manage it in writer?

MANY THANKS!!!

If the image has a transparent background then you can use right-click > Picture… > Background tab > select the required colour > click OK.

If the image does not have a transparent background then you are going to have to edit the image in an external tool. Currently the right-click > Exit with External Tool… option is not working, it will default to the file association in the OS for the file type, which for graphic images in usually an image viewer rather than editor. The related bug to get this fixed is fdo#51096. Related AskLO thread about this option is here and alternate forum thread is here.

Hello!
Many thanks!
I tried all of this, but no success!
How can I know that the backgorund is transprent?

@Glitter, from Wikipedia: “Raster file formats that support transparency include GIF, PNG, BMP and TIFF, through either a transparent color or an alpha channel.” Generally speaking, PNG is the best format to use and an alpha channel is the best method. ImageMagick can be used to determine image transparency:

$ identify -format '%[channels]' tdf-logo.png

srgba

$ convert tdf-logo.png -alpha off tdf-logo_non-trans.png

$ identify -format '%[channels]' tdf-logo_non-trans.png

srgb