It seems like there is a problem with the image uploader. If we create an Achievement (with both locked and unlocked image files picked) , they only upload correctly 50% of the time. Otherwise, we have to go back in, edit the achievement, and re-upload the images.
Hi, We haven't found any problem with the image uploader. We have tested this and are able to add images to the achievements successfully. Please make sure that you are uploading 512x512 icon size of JPG format. Thank you.