Why does the upload image return a blank page?
It is most likely that you have tried to upload an image that is too large for the Wiki. Images should be 60 Kb or less in size when using the binary file upload.
Why does Moodle Docs use MediaWiki rather than the Moodle wiki module?
See the answer to this question in the Moodle.org FAQ.
- Using Moodle Wiki module forum