Image file format in Knowledge Base article not supported

The images in the knowledge base article "How To Use SLA To Override Accounting created by AutoAccounting" are not readable. The message from all images I have downloaded and opened is "It looks like we don't support this file format". This is despite the fact that it is a PNG-file and when I tested this accross computers I always get the same message.

The steps in the knowledge base article is not very detailed and I assume the images are there to compliment the article. It is therefore very unfortunate that the images cannot be read.