With the new forum software, images can be attached directly to your post, which is certainly convenient for those pictures that save a 1,000 words.
Below, you see a series of tabs. Click on "Upload attachemnts" and you see
Locate your file with the "Browse" button, add a description and click "Add the file"
If you click "Place inline" the image will be added in the flow of the text like in this example.
That's all there is to it.
You can still link external images with the Img button above the editor, as before, but if you do so, make sure the link to the external image ends in a supported image extension or the software will not make the link active.