I have just tested by uploading/re-downloading an image, and the EXIF data is removed.

I then looked through the Lemmy issues and found this issue related to the image-uploading back-end (pict-rs) removing the EXIF data. In response to this issue, the developer of pict-res (asonix) comments that striping the EXIF data was one of the original motivations for building the uploader.

I am not sure about how to search through the source code of pict-rs, and it seems like this step is not properly documented in the readme file, so I have not been able to find exactly where the metadata removal operation takes place. I think that this is done by invoking ‘exiftool’.