I’m looking at the output, and I don’t think the “Connection closed by server” is the issue. In the logs, I can see you’re uploading various images ranging from 20-40 MB in size. However, there is a file size limit of 10 MB on free hosting, and all files larger than that are discarded by the server.
If you want to display photos on your website, I highly recommend to downscale and/or compress them. That’s both for the file size limits, but also because smaller images will load much faster and use less bandwidth of your visitors.