Another question: did you resize or compress the images before uploading them? It's very easy these days for a straight-out-of-camera image to exceed 10MB (lots of pixels, fine quality JPEG), and files larger than 10MB are automatically deleted after 4 hours. If you need huge images for any reason, a JPEG optimizer (such as JPEGmini/JPEGmini Light - that's just an example, there are others) can bring the file sizes down an awful lot without making a visible difference. If you don't need huge images (where "huge" means 20MP or more), then resizing them to something more appropriate for the web will make a bigger difference.