problem with custom page size in imagetoraster

[Luc Habert]

> > Moreover, the `header.PageSize' is not even set.
>
> Um, it *is* set on lines 945 and 946.

Sorry, I missed it. However, the confusion between page size and image size remains :
- at lines 891-892, `xprint' and `yprint' are assigned the size of the image as it will be printed
- at lines 912-922, their contents are assigned to variables `width' and `length' which are later used as if they were `PageWidth' and `PageLength'.