Re: (none)

I have looked at background images, but they don't seem to be quite what I
want.  I need to have complete control over the position and size of the
image

and I also need to be able to specify that it appear on eg first
page only, all but first and all pages.

Use a page-sequence-master with a first simple-page-master featuring
the background and the rest without it.

As an alternative, is it possible to place an image in a block-container
within the body text, but specify that it should appear on all pages, all
but first page or first page etc.

No. The only way to get something page-oriented is through page
masters and static content.

As for transparent image, I meant that the background colour of the image
should be made transparent (I believe most applications usually take left
corner pixel as background colour).

The spec leaves this to the processor and the capabilities of the
output medium. PDF can have transparent colors. You need to specify
an appropriate image format, I'd try a RGBA-PNG, setting the alpha
channel for the background to, well, either 1.0 or 0.0.