What is the format of the original source document? A Microsoft Word document?
Where did you get these images from? Are a lot of these images charts/graphs inside of the book? Did you generate these yourself?
If you have 1000+ images, and if you have access to all the source images (you generate them yourself), then perhaps PNG might better suit you than JPG (and make your EPUB WAY smaller in filesize, while making the images much higher quality/crisper).
See one of my posts/samples of a JPG/PNG size/quality comparison of a high resolution graph:
https://www.mobileread.com/forums/sho...5&postcount=26
The PNG is ~2/3rd the size, and the highly optimized PNG of the graph is ~1/3rd the size, and much higher quality than the JPG.
Is this EPUB being given away for free (on your site?) or will this be sold (your site? Amazon? B&N?)?
Ugh.. I am just thinking of the bloat/unmaintainable code that is in this EPUB... I see the Calibre CSS classes are numbering in the THOUSANDS range.