Hey there,
I am sorry for the delay of this reply,
In Easyblog 3.9, we allow admin to configure the max/min image width and height then it will causing this issue is because if I set the width to 500px and I set columns to show 3 columns, the system not able to render this is because the total width from the webpage only 940px, you can refer on my screenshot here :
http://screencast.com/t/gND4sTCQR0cc
Unless you adjust the image width to 200 ~ 250px, it will appear 3 columns (screenshot :
http://screencast.com/t/uMy2vOdB2 )
In other word, you have to adjust your image width from the module settings in Easyblog 3.x.
But we already improve this in Easyblog 5, we no longer allow admin to set the image width from the module, you can check my attached screenshot below.