Frank ... I use a Windows PC and the following works. Go to the WEB site where the photo is stored and then right click on the photo with the mouse and select copy image location ... then click on the insert image button on the VAF tool bar to bring up the image location box. Next right click inside the image location box and select paste to copy the address into the image location box to establish the link to the photo for your VAF posting.
Go to your picture at google. Right click on the picture, copy link (so not the link in the bar!). At VAF forum press on the insert image square, paste the copied link.