last time i checked, it was 2gb if you use butler and you can request a limit increase. but for that you have to show that you made an effort do decrease size. There are lots of vn that have a ton of png with 2MB that could have been 200kB jpg without any visible reduction in quality. png is "compressed" in name only. It is good for pixel art, where pixels are important. But the images you have, are best delivered to the player in a format you would use for real life photos.