I have added an image to my course description.
The original image was 275 x 187, but Moodle seems to display even smaller than that.
I used Gimp to change the image size to 331 x 225, then 405 x 275, but Moodle keeps the showing the 275 x 187 size.
Moodle does not display everything this small, in the course description, just this.
The image is not online, I uploaded it.