You have to match the lighting, color, contrast, saturation etc to make collages look natural. Its obviously really hard to say exactly what you should focus on without seeing the image.
http://picpaste.com/ will let you upload images quickly without signing up or anything.
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum You cannot attach files in this forum You cannot download files in this forum