I have installed SilverStripe-v2.3.3 and gallery-0.2.2,In the gallery page though images are showing but when i click on images nothing happen ,no pop up comes out i,e nothing happens.
I have installed the same version of gallery and SilverStripe and in that website gallery is working fine,So i think its not an issue with compatibility or server not supporting,as in the same server and client its working fine but in different website.
The instructions to name the folder as "gallery" are correct. It is important to stick to the standard. I suggest that you delete the folder "gallery-v0.2.3" on your web server and then run /dev/build to clear out any references to it. Then re-upload the "gallery" folder to the server and re-run the /dev/build to set up the "Gallery Page" type again.
Also ensure that the "gallery" folder is in the root of your site at the same level as the folders "mysite", "sapphire", etc.