I'm surprised that you get satisfactory results. I tried RH's
Resize tool, which I didn't know about, but am getting the same
result I get with other methods I've used. The problem is that, for
online use, the image must be "truly" resized-- that is, a
100x100px image must become a 70x70 image to display correctly at
70%. If I simply resize a larger image within RH, it becomes
illegible when displayed online (it appears that the necessary
percentage of pixels are just omitted). With any good resizing,
such as the RH tool, original pixels aren't randomly omitted but
are instead approximated within the fewer pixels of the new image.
This is the most legible result I can get online. But for printing,
the print operation uses all the original pixels, because a
printer's resolution is much finer-- so the original image works
the best even if it's reduced in display size. In contrast, the
image I made for online use, with fewer actual pixels, looks really
bad when printed.
Please tell me if I've missed something. Summary: in my
results, reduced-size online display requires an image of fewer
pixels that dither over the original pixels. Printing requires all
the original pixels, but packed closer by the printer.