@Clancy7325 I couldn't find any black spots, but I could try to look into it more if you elaborate a bit.
Edit: Oh, actually I see what you mean now. I accidentally left the transparency setting on during a conversion process. They appear fine when viewed on a light background, but you see dark grey spots if you view the images on the other e-hentai site. Will update soon with a fixed version.
(Also note that there is an issue with the background of one of the character CGs, but that is unrelated to this issue. It appears that the original data may have been corrupt for that image.)