Compiled ePub is Much Bigger--Because of New Version?

I have reason to recompile a project that I last compiled in March of 2014. There are 43 photographs in the book.

When I compiled it then, the resulting epub file was 12,471 KB.

When I compiled it today, the resulting epub file was 59,527 KB.

I will need to figure out why it is so much bigger now (too big, in fact). Was there some change in how images are handled? The images are linked to jpg files.

I have Version: - 11 Mar 2015 now, and back then I had the then current version.

I hope you can point me to the fix.



SOLVED: I have two sets of images, one for the paperback book and one for the ebook. I had compiled it with the wrong images.