try 'HtmlEditorConfig::get('cms')->removeButtons('ssimage')'
The following is one that I used for my last project. make sure it is insert in /mysite/_config.php
HtmlEditorConfig::get('cms')->setButtonsForLine(1, 'bold', 'italic', 'underline', 'strikethrough', 'separator', 'justifyleft', 'justifycenter', 'justifyright', 'justifyfull', 'styleselect', 'separator', 'bullist', 'numlist', 'charmap');
HtmlEditorConfig::get('cms')->setButtonsForLine(2, 'undo', 'redo', 'separator', 'cut', 'copy', 'paste', 'pastetext', 'pasteword', 'spellchecker', 'separator', 'ssimage', 'ssflash', 'sslink', 'unlink', 'anchor', 'advcode');
HtmlEditorConfig::get('cms')->setButtonsForLine(3, '');
HtmlEditorConfig::get('cms')->disablePlugins('table', 'contextmenu');
in your case, you just nee to remove 'ssimage', and 'ssflash', just take them out from the list
HtmlEditorConfig::get('cms')->setButtonsForLine(1, 'bold', 'italic', 'underline', 'strikethrough', 'separator', 'justifyleft', 'justifycenter', 'justifyright', 'justifyfull', 'styleselect', 'separator', 'bullist', 'numlist', 'charmap');
HtmlEditorConfig::get('cms')->setButtonsForLine(2, 'undo', 'redo', 'separator', 'cut', 'copy', 'paste', 'pastetext', 'pasteword', 'spellchecker', 'separator', 'sslink', 'unlink', 'anchor', 'advcode');
HtmlEditorConfig::get('cms')->setButtonsForLine(3, '');
HtmlEditorConfig::get('cms')->disablePlugins('table', 'contextmenu');