Comic Viewer is doing a few things the first time you open a comic to read:
- Resizing very large images: While iPad is a pretty powerful device, it does have its limits (e.g. RAM). If you have images larger than 2048 pixels, they will be resized to provide snappy app performance and prevent the iPad from crashing due to lack of memory. Each page will only need to be resized once.
- Creating page thumbnails: When you launch Preview, Comic Viewer will create thumbnails for each page in your comic.
While it may take a little time to process your comics, it will only happen once. The result is a quicker reading experience every time thereafter.