Scaling linked photos in CS

My answer is "it depends."

For non critical work that will be exported to PDF, scaling them down is
a non-issue, but if the native files will be sent to press, you might
want to stick to 10% or so, so that you don't wind up with resolutions
nearing 1,000 dpi which will cause some RIP delays.

This also depends on the original resolution. If you're starting out
with 72 dpi, you're going to need to scale them down to get them to
print well. The info palette will give you the original and effective
resolution on graphics.

Bob