Photo down loads

Im sure this has been asked many tomes before but Ive never tried. It.

How can I transfer a photo directly from my iphone library on to a post?

In the past i used to use photobucket but im long gone from there.

I believe there is the ability to upload a photo, but it is severely limited in size. However if you use hosting on another site, you can reference the site by copying the image location, and then clicking on the image icon when responding to a message. That's the only way I know how to do it