How to.

Not having a Tablet I'm not sure if this works on them but it works on a PC.

Have you tried dragging and dropping? (The easiest option.) If the digital size of the file is not too large then you can just drag it from the file you have on your computer to the box that you type your posts into on here. Sometimes it won't go unless you first click into the box before dragging

It will then show a small, rolling, symbol in the top right hand corner of your screen to show that it's working on it. Then it drops it into the box as a thumbnail with the option to click on 'thumbnail' or 'full size' (or words to that effect). Click your cursor where you want the picture and then pick your option. It should always be full size if you can as some people won't bother to look at thumbnails.