RESOLUTION:
Images in Page Body appearing as 'x' mark in IE browser
After migration,image in the page body appeared as 'x' mark in IE browser.
This is known issue for IE Browser:
Image in body field of some documents gets migrated but does not render in IE
it renders fine in Firefox/Chrome though.
Quickr shows image by using special JavaScript. It is not just an <IMG> tag.
So it is possible that Quickr works, but SharePoint doesn't.
Also, the Quickr changes the image file extension as jpg even if you upload it
as a PNG image file.
A workaround is to use Firefox/Chrome