Method 1: Email the photo to yourself, then access that email on your computer.
Method 2: Connect your mobile phone to your computer, using the same USB lead that you charge the phone with. Your computer should then see your phone as an external drive (in just the same way as if you'd plugged a memory stick into it), so that you can copy-&-paste (or drag-and-drop) the file between the two in the usual way. [NB: With some phones it's necessary to go into the settings and select 'MTP mode', or something similar, to get this method to work. The manual for your phone should tell you].
Once you've done that, the easiest method to show us your pic is to upload it to here
http://upl.co/
copy the 'Direct' link and then paste it into an AB post.