Wordpress isn't uploading Full-Size image

I always uploaded my photos in WordPress for ex. 15mb Photo up to 20mb Photo and now Wordpress is automatically optimizing my photos to 1mb. I'm not sure but I think after the last update this is happening. I really need to upload the full size Photo of 15mb or 20mb or more. I tried to research but couldn't find anything exactly that helped me. Anyone that had this problem and fixed it?
@Festinger (tagged you since you are the King of Wordpress here =D)