Office Excel 2003 adn 2007 issues

at my work we have 4 computers running MO-03 and 2 using MO-07 trial. we use excel quite a bit with imported images (.jgp and .png) in the worksheets. when a file is created in 07 it seems that the images don't compress down very much (double clicking the image and selecting the compress button in the general tab) and when printing and opening these files on a computer using 03 the images have moved from where they were first placed on the page. in addition the images are able to be compressed quite a bit then in 03, there have been files that are over 1MB that compress down to 600-700 kb. note that this is all while saving as .xls (not the new format, i don't recall the extension right not) files, i have changed the default save as such.

has anyone experienced this? i have searched on the internet to find solutions or answers of why it would behave differently but have not found any.