I played around with "Google Photos" today and found that if you do the following your pics will come up ok on the forum
1/ open google photos (der )
2/ select the photo you want to put in the forum
3/ Left click in it (that will open it in a different view)
4/ Right click
5/ Select "copy image location (left click )
6/ Open forum posting window
7/ Left click on insert image icon
8/ Right click on the dialogue box (NOT on the orange bit, leave that there ) and paste
9/ Left click "OK" You're done