We recently discovered a bug that affected free account holders and fixed it.
The bug was that when reuploading an image with the same filename as an existing image, the original image (with watermark) would remain online.
The image was actually uploaded to our file servers, but was not activated as the most current version, keeping the old image online instead.
This bug has been fixed, when you reupload images with the same filename but different image data, the new image data will be shown (with watermark).
