but like Bob I find it hard to understand the main problem. I attached a screenshot about your previous post and some numbers... what do you mean by "preview" (1) that displays your code?
- do you mean that your current tex filter does not render equations (2) / (4) somewhere/anywhere? In wiki of moodle square brackets won't work but elsewhere your tags are valid if your tex filter is just parsing tex either with mimetex executable or some server side distribution of latex that has correct paths and permissions in your tex filter settings. Here in moodle.org is rendered with teTeX that uses sometimes different syntax than mimetex in folder filter/tex/ if your site is using mimetex but mostly all distributions use same syntax. Some extra white spaces or unicode characters or html code inside latex tags may sometimes cause failure...
- if you just copy images from clipboard like (3) they can't work elsewhere than in your own PC... (3) is stored to temporary files of your PC. You must save the images first (to your hard disk) and upload them to course files of moodle (moodledata) for example with image plugin of editor or use external links to external images with image plugin
- or do you mean that editor (htmlArea) shows only code, not WYSIWYG (that's normal behaviour of HTMLArea) ? (5)
- or do you mean that you have copied a link to an image from some other site or course like in the article Bob mentioned and the image is not shown or given equation is not seen in preview window of editor image plugin? (images from other courses won't be seen unless you have visited that course and the image is in cache...)