help!

i was currently asked to take some pictures for our company website. 

and let say i did my best to the fullest of what i know. but when we upload some pictures in our web, there was a little problem. the resolution of the thumbnails is not that good. or should i say it is very very not good. 

i upload it in my photoblog and it seems that it is alright. And so i upload it here for you to see and for you to judge. 

i asked my mentors why does that happened?

but no one could give me an answer.