Number of results
Google Image search returned 9910 results for 'vidhana soudha' while Bing returned only 2380
Google Image search returned 198000 results for 'manmohan singh' while Bing returned only 51500
Google Image search returned 78100000 results for 'obama' while Bing returned only 8750000

Relevant Results
Google's Image Search throws up far more number of relevant images than Bing Image Search
In most searches I tried Bing and Google both returned relevant images upto the first 10-15 results but
from there on Google's results were still relevant whereas Bing results were offtrack


Filtering Options
Bing has more filtering options (based on size , layout, color, style and people )compared to Google but Google filtering works well although the options are limited.


Result Layout
Bing has 4 options for the results layout. 3 of these are zoom levels and the fourth is Image with details. Google provides you the ability to see the image details irrespective of the zoom level.

Bing has a long way to go before it can attain Google's popularity levels.