The imagetransfer.py script doesn't expose options for UploadBot's asynchronous and chunk_size arguments, which means it cannot be used to transfer files larger than 100MB (use case was a >1GB PDF from Commons to Wikisource). It'd be nice to expose these options as command line switches that are passed through to UploadBot.

Looking (quickly) at the code it looks like it wouldn't involve much more than mapping the command line switches to UploadBot arguments and adding them to the docs, provided UploadBot does its own validation of these argument values (which I didn't check).

cf. T129216 (and CC to possibly interested parties)