Trouble linking in-line image

[johnnyboy 3742]

I'm trying to post an image in another thread, but it doesn't work.  This is how I am specifying it (without spaces):

 

[img ]https://www.dropbox.com/s/g3y5skf46lcx9g4/pirates_w_hostage2.jpg[ /IMG]

 

It doesn't work, it displays the file name instead:  pirates_w_hostage2.jpg

 

However, in another thread, I posted a similar link that works perfectly to display in-line image:

 

[img ]https://dl.dropbox.com/s/uy6qp5lwl27uh1r/end3.jpg[ /IMG]

 

Both files are < 100Kb.

 

Why does my first image link not work?

 

Please advise.