For Photos to;Lit P.M. -- Tumblr Hosting
I have a Tumblr blog that I use specifically for this purpose. I can upload a photo/GIF from my hard drive. Or I can load a linked URL to my site. And then, when making a Lit P.M., right click on 'copy image address' on my site to enter in to the 'Insert Image' box in the P.M. message dialog.
Also use my Tumblr as the intermediary for images to post on Lit threads.
Not hard once you get it set up.
This also works great when in a private conversation in Literotica Chat.