I did get a moment, uploaded several images, and they seem to have gotten lost. Possibly I shut the browser down before the upload finished. But, yes, the same issue occurs on Windows. It’s apparently an old issue, which perhaps has never even been discussed. Unfortunately, “RGB” is not standardized. (That has been discussed.) The common treatment of RGB data which doesn’t have a profile is to assume that a 𝛾 of .45 has been used, and reverse that on display by applying a 𝛾 of 2.2. Julia doesn’t do that.
Here’s a discussion of why using 𝛾 makes sense when using 8-bit RGB data from a photographic web site.