Apart from the appearance of the buttons (a bit brighter blue) nothing changed in recent updates. At least not that I'm aware of.
Anyways, I tried to explain things a bit in detail in this post: https://pinside.com/pinball/forum/topic/cant-rearrange-pictures-in-for-sale-add#post-4697656
It boils down to this: if you don't care about the order of images, simply upload an image and hit "send post". No need to manually insert the image in your post text, as the system will do it for you.
If you *do* care about the order of images attached to your post, you can drag drop them to re-order, then hit "send post" and the system will add the images to the bottom of your post in the order you specified.
Finally, if you need exact control of order and position of your images, you can also insert images into your post text by using the + link. The code for that image will be inserted at cursor position.
Now stop yelling at your computer and play some pinball!