This tool can be regarded as Web-based Front End to the jpegtran utility for lossless JPEG transcoding from the Independent JPEG Group . Only reversible image transformations are performed. Otherwise, you can't choose a local file for upload in the above input field. No problems with concurrent client requests.
Simultaneous accessibility is limited only by Server configuration for CGI processing.
Maximum efficiency with minimum transfer, storage and processing overhead. Since the returned image does not have a unique URL, you must explicitely save the image per Browser menu if desired. Unfortunately, there are some unsolved problems regarding the client cache behaviour. This is odd.