Ensuring ePub conversion doesn't touch images
My very first eBook ( http://www.lulu.com/shop/alexander-karasev/roundny-the-round-project/ebook/product-22104130.html ) displays photos that have a pixelated, jagged quality to them. The product page has a preview ePub that shows the same problem. In my source document, the images are 300dpi high resolution photographs, themselves carefully scaled down from 36MP originals with no artifacts.
After the Lulu ePub conversion, the images do not look good enough for a photo-oriented ePub ebook. I have perused the Lulu Complete eBook Creator Guide pdf. The images in my resulting ePub clearly have a MUCH lower quality than that described in the "High-Quality Images" section (250 KB and 2 megapixels), so I have the following questions:
1. Exactly what conditions trigger ePub image conversion? Is it total image size in megabytes, image pixel dimensions, image pixel size relative to its size on page (i.e. dpi), total ePub file size, or a combination of these thresholds?
2. What are the specific threshold values?
3. What are the steps to make sure Lulu ePub conversion does not touch the images?