Yes, you're right that Robohelp extracts the equations as
images but it does a lousy job of it. They seem to be extracted as
extra-large GIF images that are then resized in the help file, and
it is the resizing that messes up the quality. If you take a screen
dump (as BMP, not GIF) and add it to your Robohelp for Word
document using Insert Help Image (which oddly cannot handle GIF
files), the inserted image is extracted as GIF to the
SSL\Webhelp\images folder at the correct size, and the quality in
the help file is the same as the quality in the screendump.
When I did this with a fairly simple small equation, the GIF
file extracted from the Microsoft Equation version was 2528x864
pixels (yes, the width of 2 high resolution screes), while the GIF
file created from the corresponding screen dump was 112x39 pixels.
Don't as me why - but the GIF extracted from the original equation
does have excellent definition at its actual size
!