The old galleries, pre- 3.5 Wp are working fine.
Making a new gallery with photospace doesn’t seem to work, most likely because there is no longer this function in media,

Click the Add an image button upload the images but you don’t need to insert them into the content. You can just close the add an image window when finished. Or click save changes and organise the images with the new gallery tab.

Ok this time it worked.
So Add Media, Upload images, Add captions, add alt, click the edit button on the bottom when finished, order, then X out the window.

[photospace]