I am using WYSIWYG Image Upload (http://drupal.org/project/wysiwyg_imageupload) + WYSIWYG (Newest Dev) + TinyMCE (newest stable), and it seems as though through its use we may have discovered a bug in the WYSIWYG plugin API with TinyMCE.
Basically, in Internet Explorer 7 or 8, whenever an image is inserted via the WYSIWYG Image Upload, the image is inserted in Row 1, Character 1 - regardless of where the mouse cursor is in the TinyMCE document. When using a browser like Chrome or Firefox, this doesn't happen - the image inserts wherever the cursor is. When switching to a different editor such as CKEditor, it works as expected in Internet Explorer.
Anyone experience something similar / have a fix?