Wiki FAQ
From MoodleDocs
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 Moodle.org FAQ.
See also
- Using Moodle Wiki module forum