Click on "Go Advanced" under the quick post. Scroll down the advanced posting page to "More Options" click the button "Manage Attachments" this brings up a standard upload file form. Use it to upload pictures.
After the file uploads it will be listed under the form and be listed above the manage attachments button. It will appear as a thumbnail under the post.
For more control over placement:
One can copy the address of the image link. Windows
right click on link & select copy link. Not sure what it is on Mac but it is available there too. Or one can open the link in a new window and copy the address. Put the URL address in using the picture icon along the top of the advanced post edit window.
This is nice when you want to place the image with text around it explaining the picture. Algonac Mich. Rally
logo from 2018 was canceled last year but date will get changed for this year
See this is inserted in the text using the picture icon and link address copied after adding the attachment.
One can also just go to photo albums and upload pictures then copy the code from under each picture to paste into the post. I do that for pictures of repairs when questions arise on repair that I took pictures of while doing them. They get reused.
The picture below was added simply because I uploaded it as an attachment in the advanced post form