Dropbox and possible file-size limit?

I teach architectural history at a local university, and use .ppt presentations for my lectures. File sizes range from 20 MB to 45 MB. I store all of my files in Dropbox, since I am constantly switching between my MBP and the university's PCs in various classrooms and need to be able to save edited versions back to Dropbox. I have an iPad, and would love to use it for reviewing .ppt presentations before class (i.e, not to edit, just view). The problem is that, at about 20 MB or so, which is generally about half the file, images don't load anymore. The .ppt slides (and usually text) load, but about halfway through, no images. I've inquired on Apple Discussions, but no solution. Is there a maximum file size that I'm bumping up against?
Solutions which involve me having to download onto the iPad via iTunes are not satisfactory, as that version of the file isn't stored in Dropbox, and won't have subsequent edits.
Any thoughts?

 

the problem is that Dropbox is my 'central' storage site for the files. if i download one of my .ppt files from DB onto the iPad, regardless of what program i open it in, only half the images load. i don't want to edit on the iPad, just view the file: i'm editing on other machines (several), and thus the value of DB is that it saves the most recently edited version, regardless of which machine i'm on.

 

Thanks. I'll give it try later today when I rejoin with my iPad...crossing my fingers...!

 

Thanks for the tip...works like a charm! I now feel that my iPad is 100% functional for what I need it for! Except...now that I have Keynote, it would be great to be able to edit those .ppt files on the iPad, export them to .ppt from Keynote, and save to Dropbox, so they'd be accessible from other machines. Is that possible yet?