I have a free MediaFire account so that I can upload my EAW stuff for people to download.
I also use it for pictures.
When I upload a picture and the upload has finished I click on it in the MediaFire folder.
MediaFire displays the picture, and when that happens i right click on the picture and this gives me an option to copy the image URL in memory, which I do

I have a text file which already has a heap of [img][/img] lines in it, so I paste it between the [img] and the [/img] and then save the text file.
When I want to put it in a post I copy the line from the text file and paste it into my post.
I am sure this can be adapted by people who have other online storage facilities

Jel