Yep...only way. To have it hosted online and paste the picture URL in the message by using the Insert Image option.
You can put a pic in the media section here on the GTA then add a link to it in your pm..... I think. I'll send you a test to try it....There ya go, the actual pic is not in the PM but, just click on the link and it takes you to the pic.The thing I like about this method is I'm not putting my stuff out there and getting a bunch of garbage in return.And for others.... this is the link I sent in the PM....https://www.gatewaytoairguns.org/GTA/index.php?action=media;sa=item;in=5192