Yes, I was aware of Annotate, but I'd used draw in the command line version and there it worked. Annotate will suffice, but I'm still puzzled that the Draw doesn't work. The documentation does not seem to describe a way of supplying the text to be drawn for Draw and supplying the text as (... text=>"Hello World", ...) generates an error to the effect that "text" is not a valid parameter (I've not got the code here).

My other question is: how do I generate 50% transparent text? Have I to do it by generating the text in another image then compose the two images together, or is there a more direct way of generating partially transparent text on an image?

An even more fundamental question is: How do I generate a "blank" image that I can draw on?