Image URL breaks via XML-RPC

Since a couple of weeks I see that the image URL’s break when adding or editing posts. I normally use MarsEdit, but the same behaviour also happens when using Ecto. What happens:

I make a new post in MarsEdit and use the Media option to select and upload a new image. In the preview I see the image correctly, and the image is stored in the gallery server side. The following URL is shown in the post:

<img src="https://littled.nl/wp-content/uploads/2008/12/dsa000051.jpg" alt="DSA00005.JPG" border="0" width="431" height="284" />

I press ‘Send to weblog’ and the post is succesfully uploaded. But… when I check the blog, I see the following text instead of an image.

img src="https://littled.nl/wp-content/uploads/2008/12/dsa000051.jpg" alt="DSA00005.JPG" border="0" width="431" height="284" />

The source code of the HTML page states the following:

img src=”https://littled.nl/wp-content/uploads/2008/12/dsa000051.jpg” alt=”DSA00005.JPG” border=”0″ width=”431″ height=”284″ />

– the trailing < is removed
– the ” are encoded

Now, when I create a post via the WordPress web interface and insert an image into the post (e.g. the image I just uploaded into the gallery from the previous exercise), the post shows up correct. Even when I refresh my MarsEdit posts (and retrieve the post just created in the web interface), this post shows correctly. But… when I send the post back from MarsEdit the post gets the same problem.

I tried it with Ecto to see if it’s an problem with the client, but Ecto has the same problem also. Even when I tried it on a different Mac with a fresh install of MarsEdit, it has the same problem.

If upgraded to 2.7 of WordPress to see if this offers a solution, and it did not. So I even had this problem in the 2.6 version. I checked all the settings in the WordPress admin to see if there were strange settings, but I didn’t see anything obvious.

Any suggestions how to solve this problem?