I had a bunch of PICT resources that I didn't want anyone to muck about 
with, or copy, etc.

I'd been trying to work out a way of converting these to another non-obvious
resource type, and even went as far as starting to write a conversion
program. As far as I know, ResEdit doesn't allow you to change resource
types.

But the feature is already is Resourcerer. Just select all the PICT
resources, and change them to the new Resource identifier, such as "FRED".
Then use GETRESOURCE or GET1RESOURCE instead of GETPICTURE.

Easy Peasy.

Phil.