Two shades of beige

The most common situation - we can call it the default here - was that

with the screen set to thousands of colors, I saw two shades of beige in the graphic, Photoshop's half was the same as the page background.
in 256 colors, I saw the page and the whole graphic as the same continuous beige

And Photoshop's beige was the same as the page background in all cases except one oddity.

In Home Page on the Mac and the PC

In Netscape on the Mac

in 256 colors - default
in thousands of colours, I saw two different things at different times: at first it showed me both parts the same, but darker than the page background. After I'd added the centre lines in the graphic, it showed me two different beiges.

In Explorer under Windows 95

at both screen resolutions I saw two shades of beige in the graphic. Using Mac OS8's 'web-safe' beige produced a dithered color even with thousands of colors .

In Opera under Windows 95 - at both screen resolutions I saw two shades of beige in the graphic, though at 256 the 'OS8' color was a yellow.

So my sad conclusion is to abandon the lovely OS8 color picker for web design - which was the real point of using it...