If making initial post, scroll below the text entry box, look for button labeled “Manage Attachments” click it and add photos from your device just as you would from a PC onto any other site.
So, after clicking Manage Attachments, then on next window, click “Choose File” button, then once file is chosen, click “Upload” then after it uploads successfully, click “Close Window” which will bring you back to your post; once you save your post, the thread will contain the photos.
Now, if you have already made a post (like you did here) and need to add pics, click “Edit”, then under the same text entry box, click the “Go Advanced” button, then click the “Manage Attachments” button and follow same instructions as above.
One more note - if adding photos in that manner, I think the photo size limitation is (or was) 1900x1900 pixels. So if your photo is larger, use your mobile device’s photo edit to crop/make smaller OR a photo edit app.
No need to host or post photos via 3rd party web sites...