If a popup blocker appear on the top of your explorer just click on it and select the "Allow Blocked Content", (as indicated on the picture), if you still could not be able to enlarge the Photo follow the below instructions
If you are using Internet Explorer:
Go to the Tools menu.
Select Pop-up Blocker.
Click Pop-up Blocker Settings.
In the Pop-up Blocker Settings window, type mekelle.net and click the Add button.
Close the Pop-up Blocker Settings window and all Internet Explorer windows.