I am trying to get all assets inside a  collection how to do that .

yes i am working in 6.2 and thanks for the link

how can i limit the size and the quality of the image displayed?

I have checked the permissions as i have logged in through admini have all the permissions .Still getting the same error though.

While building a package in AEM using crx package manager throwing an error "package build Undefined". But when I check under etc/packages/mypackages , package was created. Even there is no error or exception in error logs. How can I resolve this issue.