Can anyone tell me how can I scaling down some pictures I have to smaller versions with out loosing the creattio date/time on the file. This is because I have taken some very large photos and I would like to georeference smaller versions into JOSM?
On the video Photos in JOSM at http://showmedo.com/videos/video?name=1800040&fromSeriesID=180 Steve tals about this, but didnt tell us how to do it.
Thanks,
Manuel. 
This tutorial tells you how to download and install Xnview, which allows batch resizing among other things, and it appears not to effect the metadata.
[edit] You can download it from here
if you use Linux (I think you are) you can use jhead to copy EXIF information from one JPEG to another so you do it like this:
convert IMG_0111.jpg -size 1024x768 scaled/IMG_0111.jpg
jhead -te IMG_0111.jpg scaled/IMG_0111.jpg
Or as a script
mkdir scaled
ls | xargs -iASD echo 'convert ASD -size 1024x768 scaled/IMG_0111.jpg;jhead -te IMG_0111.jpg scaled/IMG_0111.jpg '|sh
PS. Did you get GPS logs from your Garmin?