It's normal for the filesize to be greater that the "strictly needed", because
BitmapRip doesn't attempt at all to "clean" them. Simply opening the extracted bitmaps with any viewer / editor (even the simple Paint application that come with Windows) usually is enough to adjust the size to the correct value.
If for "small", you mean that probably only the thumbnails got extracted, that's an issue that may happen with the current release of my tool. I'm going for a totally different and much improved scanning algorithm for a next version.
About this, since I'm in need of files in witch this issue manifest itself, I'll be glad to do some testing with your file (if it contains "sharable" / non sensitive images, off course).
Thanks,
Bye!