Trouble using tree icon to link to pics on Photobucket.

I am a new member, having no luck trying to insert images from my Photobucket account. The sad results can be seen in the first few replies on the following thread:   Anyone ever used a dough knob, described in Laurel's Kitchen Bread Book? | The Fresh Loaf

I eventually was able to edit the original post and use the uploader to get the picture in, but don't understand what is going wrong with the tree icon method. I have been able to link to photobucket on a number of other fora, but here when I   drop the URL into the appropriate window and click on "insert", I get the dreaded spinning beachball (on a Mac that means the window is frozen, and you can see the result in the above thread. Any suggestions?  I'm running Safari 10.0.2 for a browser.

Thanks,

Dan