From this thread in the Trade Me discussion forums a user noticed that on "new" Trade Me (which is being progressively rolled out to users) HTML img tags are allowed in descriptions.
Further, the HTML img tags can be externally hosted. Indeed, the listing they stumbled upon this feature with is using an externally hosted dynamically generated image which logs the user's IP address, some product reference, and the referer.
Really posting this in case it catches the attention of a Trade Me dev or somebody with the ear of one, trying to send this through the Trade Me support would almost certainly go over thier head and get no where.
Link with an external image, scroll down to the "Common Questions" image
If you load that image in an incognito tab so there is no referer you'll get an error giving away the code they are using to serve it....