Q I am trying to prepare by book for publishing by Amazon on Kindle. They require illustrations to be converted from sRGB to RGB before they are uploaded. How can I do that?
A Strictly speaking, what they are asking for does not make sense.
RGB is a colour system, just as is CMYK, which is commonly used for printing. In contrast, sRGB is a colourspace, that is to say the area within a colour chart within which colours are represented; there are many other colourspaces, such as Adobe RGB, and they are usually device-specific, as each device capable of handling colour can cope with a certain range of colours: its colour profile or colourspace.
What they most probably mean is that JPEG and other graphics file formats should be ‘collapsed’ so that they do not rely on an attached colourspace or colour profile, such as sRGB. All good graphics apps should offer this as an option when saving JPEGs in particular: in GraphicConverter, for instance, you should ensure that you check the boxes to Save web ready, and Merge color profile into image.
This makes it easier to generate the output file, although by losing the colour profile it also means that the quality of colour rendering will not be as good. Such are the compromises made in electronic publishing.