I tried, but size it's almost the same for the covers and look better in PNGYou can use JPG files instead of PNG files to crop a good amount of filesize.
I used a old Lua module for AMS to auto-convert, will try PNGGauntletThat depends on the content of the image actually. Images with lots of color variation, like photos, compress better with JPEG, but images with lots of solid colors will compress better as PNG while also being lossless and preserving transparency. You can use a program called PNGGauntlet to find the most optimal PNG compression matrix as well, further optimizing your file sizes.
No, it's warez, but...........if you have the original cart and wanna dump it and make a cia............for your own use............A Bravely Default Cia is legal ?