Improve speed of uploading images

Yes, the junction does not solve the issue. As workaround at the moment, if feasible, you could try to import, on the computer where the user folder has a space, with the flash image library dashboard.
Starting from today you could find the flash dashboards blocked, there are some steps to unblock them that are documented at this link -> BigFix - Flash announcement
in the section “How to enable Allow List mode for Adobe Flash Player”