[dwig]

I would suggest that before you slap this ePub with a batch resize you should take a look at the image sizes and see if there is a set, possibly small in number, of "bad apples".

Since an ePub is a ZIP container you could do the following:

1. Create a copy of the ePub
2. Change the copy's extension to ".zip"
3. either Extract the contents or simply view the contents of the ZIP (depends on the abilities of your OS)
4. Sort the "/images" folder by size
5. View the sizes

With some OSs you'll have to Extract the files to get full control of how the folders are displayed. You might find that there are only a limited number of images that need most of the work.