When you read ‘Read i.ytimg.com’ at left bottom corner of firefox browser, don’t be worry for any thing wrong with your internet connection or your wordpress blog or websites.
This problem comes sometimes when you open a webpage or wordpress blog, that contains youtube video. Actually this sometime indicates that you need to click the play button of youtube video. After clicking the play button the “Read i.ytimg.com” problem will be solved.
Don’t think that at all other element of website is waiting for i.ytimg.com to complete. This is not true, Other element of your webpage will be loaded before finishing the above message.