combining image files into a pdf

[David Timms]

Hi, I have image files of type:
- png
- tif  (b/w) - fax like
- jpg
that were produced by my scanner, during scan of a document.

I've tried a few ways to achieve this, with limited results:
- gscan2pdf: all png pages have a strong purple tint.
- tiff2pdf: works for the tiff files
- pdfedit: needs a pdf to start with, so not much help
- pdf chain: uses pdftk to do manipulations; generates 0 byte pdf, 
output dialog seems to hang.
- oopresentation/draw: doesn't like the tif files.
and a few attempts with command line tools.

I haven't found a way to (easily) combine those into a pdf. I would like 
to know if Fedora has such software already packaged, or another linux 
app that could perform this ?

DaveT.