Selecting an image in the uploader and inserting in a post always sets the src link pointing to the original size image file, not the thumbnail or medium resolution file as selected via the radio button:
<img class="alignnone size-thumbnail wp-image-5" title="Ein Bild" src="http://<MY_WEBSITE>/wp-content/uploads/2008/04/einbild.jpg" alt="" />
However, the class information shows that thumbnail size was correctly selected. The Thumbnail file does exist (named "einbild-150x150.jpg"), and there have been no errors during the upload/resize process before.
I already made a new, completely fresh wp 2.5 install with default theme to test this, but the problem remains. Even setting directory and file permissions to 777 for wp-content and below does not change this behavior.
Anybody else here with this problem - or a solution?