Hello Navya
from what I see in your left pane menu, items are not displayed as it should be as in the standard theme template 'SAP Tradeshow'
Have you a customized theme template ? You can go to the Theme Editor in Content Management -> SAP Portal Display -> Portal Themes to find out if you have a customized theme.
For instance, the right size for images definitely matters. You can compare your images with sap tradeshow images (you may download the theme to your computer and compare them with your images)
Sizes are described in following SCN thread: http://scn.sap.com/thread/2094190
Best regards,
Johann