What size images should I use?

FlippingBook Joomla Component allows to show two different images on pages - one image for normal state and another for zoomed state. Small images size must comply with the book size (book properties > Parameters (Basic) tab > Pages Width / Height parameters). Large images must comply with Zoom Images Width / Height parameters (book properties > Zoom setting tab). You'll get the best quality and performance in this case. Don't use images larger than 2800x2800px

Images for pages

Images for zooming

You can set desired image for zooming in the page properties (Components > FlippingBook > Manage Pages > open the properties of page > set Zoomed Image).
You can also set enlarged images automaticaly when you creating pages uses Batch Add Pages feature (Components > FlippingBook > Batch Add Pages > set Mode - Advanced and specify prefixes as illustrated in Usage Example).