Problems with images in Lightbox... please can you help ?

Im having a few issues with my light box ...
have a look at the link- any info or ideas would be great..
http://magdalenabrown.com/Lightbox/BOX3/test_12.html

1 - It seems my images are being resized automatically in light box.
some come out ok, some do not. there either getting resized or coming out with masses of white space around them. as if the image and lightbox are not communicating about the size of the image

2 - Also my back ground is not coming out transparent. ? no idea why ..
and its making me nuts. :yikes:

3- if i was wanting to change between Lightbox V2.03.3 and V2.04
can i just replace the files or do i need to change the code in the html doc
as well ?