Loading screens are graphics, that are shown when the client is loading map
data, before entering the game or while changing maps.
They are located inside the [GRF] in data\texture\À¯ÀúÀÎÅÍÆäÀ̽º
(data\texture\유저인터페이스), must be of type JPEG and have to be called
loadingXX.jpg where XX is a zero-based index (00, 01, 02...) and limited
to about 6-12 files depending on langtype (unless you have diffed Unlimited
Loading Screens option).
You should prefer sizes of 4:3 (ex. 800x600, 1024x768) otherwise the loading
screen is stretched to fit the screen, which causes certain quality loss. Try
to avoid gradients, because the client reduces the amount of colors used
inside the image as well.