Right now MediaViewer's "Open in Media Viewer" button is placed directly below the preview image on file description pages. This needs to be changed!
Rationale: File description pages should contain information specific to a file (that's why they are called "file description" pages). Navigational elements that are not specific to the file should go into one of the designated navigational areas.
Right now (especially when other extensions/gadgets are active on a Wiki) file description pages often are structured like this:
"preview image > button > another button > MediaViewer buttton > button > description" (find the error...).
Please note that this change was already agreed on by WMF staff back when MediaViewer was first enabled, see
Re-evaluation of the buttons position was promised multiple times by Fabrice Florin, however until today nothing has changed!